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The coronary artery bypass experience: gender differences
The coronary artery bypass experience: gender differences Patricia A. Keresztes, PhD, RN, CCRN,a Sharon L. Merritt, EdD, RN,b Karyn Holm, PhD, RN, FAAN,c Susan Penckofer, PhD, RN,d and Minu Patel,b Hammond, Indiana, and Chicago, Illinois
OBJECTIVE: The primary purpose of this study was to examine differences between women and men on physical, social and psychological domains of health quality of life before, 1 month after, and 3 months after coronary artery bypass surgery. DESIGN: A prospective, longitudinal design was used. SETTING: The study was conducted at a Midwestern, 500-bed community hospital with an ongoing cardiothoracic surgical program. PARTICIPANTS: Forty pairs of women and men matched on age within 5 years and body surface area within 0.1m2. INSTRUMENTS: The physical, social and psychological domains of health quality of life were assessed using the following instruments: Ferrans and Powers Quality of Life Index, Specific Activity Scale, Symptom Scale, Profile of Mood States, Overall Health Rating Index, and Personal Resource Questionnaire. RESULTS: Both women and men improved on physical and psychological measures following coronary artery bypass surgery. Compared with men, women reported more shortness of breath and depression and lower ratings of activity, vigor, and overall health. Measures of social support yielded little information. CONCLUSIONS: Despite matching for age and body surface area, women did not have as favorable an outcome after surgery as men. Continued research needs to further examine the interaction of physical outcomes and depression in women after coronary artery bypass surgery. (Heart Lung® 2003;32:308-19.)
INTRODUCTION Fifty-eight million people in the United States, or 1 in 5, suffer some form of cardiovascular disease, the number 1 killer of both men and women1. Cardiovascular disease claims the lives of more than 500,000 women every year. Data obtained from The Society of Thoracic Surgeons2 revealed that the number of women undergoing coronary artery bypass surgery (CABS) is gradually increasing. Studies on outcomes in patients after CABS have examined both physical outcomes (such as operative mortality, symptom relief, graft patency rates, functional From the aPurdue University Calumet, Hammond, Indiana, bUniversity of Illinois at Chicago, Chicago, Illinois, cDePaul University, Chicago, Illinois, dLoyola University, Chicago, Illinois, USA. Reprint requests: Patricia A. Keresztes, PhD, RN, CCRN, 606 Chauncey Court, Mishawaka, IN 46545. Copyright © 2003 by Mosby, Inc. 0147-9563/2003/$30.00 ⫹ 0 doi:10.1016/S0147-9563(03)00101-8
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status, and return to work) and psychosocial outcomes. The results of many studies cited in the literature review section indicated that women do not have as favorable outcomes after CABS as men.
PURPOSE The purpose of this study was to determine if there were differences between men and women undergoing CABS matched on body surface area (BSA) (within 0.1 m2) and age (within 5 years) on the physical, social and psychological domains of health quality of life (HQL). Observations were made immediately before surgery, at 1 month postoperatively, and at 3 months postoperatively.
LITERATURE REVIEW The literature is replete with studies comparing the outcomes of women and men undergoing CABS. Though the majority of these studies does not spe-
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cifically focus on quality of life, it does examine various dimensions included in the conceptualization of quality of life. Physical outcomes studied include mortality, relief of symptoms of angina, shortness of breath (SOB) and fatigue, and exercise capacity. Several studies reported women have a higher operative mortality after CABS,3-11 whereas other studies found no differences in operative mortality between genders. 12-16 Various hypotheses accounted for the differences in operative mortality found between men and women. These include that women had smaller coronary artery size, had poorer revascularization, had smaller body size as measured by BSA, had increased rates of diabetes mellitus and congestive heart failure preoperatively, and were older.7-10,12,15,17 Several studies showed that, in addition to an having an increase in operative mortality, women do not experience the same level of symptom relief as men postoperatively.18,19,20 Rahimtoola and colleagues18 reported that women had a lower incidence of being angina free after surgery compared with men. Sjoland19 found significantly more men than women reported being free from SOB 2 years after CABS. These authors also found women reported a higher frequency of chest pain compared with men at both 3 months and 2 years after CABS. Sjoland20 reported that men performed better on, along with mortality and symptom relief, exercise tests both preoperatively and at 2 years postoperatively. The improvement in exercise capacity between the 2 time periods was also greater in men than women. Other investigators21 reported that women had less favorable physical functioning and ability to carry out activities of daily living compared with men before surgery. Therefore, on many measures of physical outcome after CABS women have been shown to have poorer outcomes than men. The psychosocial aspect of quality of life in patients undergoing CABS has also been reported in the literature. Psychosocial outcomes studied include depression and work status. Consistent with physical outcomes after CABS, psychosocial outcomes studied revealed that women do not fare as well as men after CABS. One study specific to gender differences after CABS found that fewer women than men returned to work at all postoperatively, and women who did resume employment took an average of 1 month longer to return to work.22 Others reported both more preoperative and more postoperative depression in women compared with men.21,23 Few studies have focused on gender differences in quality of life after CABS. The studies specific to
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quality of life after CABS are prospective studies that include the physical, social, and psychological dimensions of quality of life. However, there is a paucity of studies that address gender differences in the measurement of quality of life before and after CABS. Three recent studies specific to quality of life all reported improvements in quality of life measures after CABS.24-26 Ross and Ostrow24 measured mood states using the Profile of Mood States (POMS) and quality of life using the Quality of Life Index (QLI) in subjects before CABS, 6 weeks after CABS, and 3 months after CABS. The authors reported that, after CABS, subjects’ perceptions of mood states, physical and social functioning, and quality of life improved compared with perceptions before surgery. There was no report of gender differences. In addition, Hunt et al25 reported significant improvements in quality of life measures 12 months after CABS. Quality of life measures included physical functioning, social functioning, and pain. Once again there was no report of gender differences. Lastly, Karlsson et al26 reported improvements in the quality of life measures of depressed mood states, stress, and anxiety after CABS with no references to gender differences. Specific to gender differences in quality of life after CABS, Luquire27 examined 49 female subjects and 80 male subjects at 3 and 6 months postoperatively. Subjects were not measured preoperatively. The author found that women reported more severe cardiac symptoms, however there were no differences in reported quality of life between women and men at either time period. The literature review reveals disparate findings regarding outcomes of women compared with men after CABS. Many studies have been retrospective in nature and few prospective studies have focused on gender differences in quality of life after CABS. In addition, many factors have been hypothesized to account for poorer outcomes in women. Two of these, age and BSA, have been controlled in the study. This study is intended to address this gap in the literature by controlling for age and body size and focusing on gender differences specific to quality of life before and after CABS.
CONCEPTUAL FRAMEWORK In conceptualizing disease impact and treatment outcomes, Ware28 advocated the measurement of physical, mental, and social health and well being. Physical measures include personal functioning, role functions, disability, and self-rating of health and physical symptoms. Mental outcomes include
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Fig 1 Health Quality of Life (HQL).
positive affect, psychological distress, and psychosomatic symptoms. Social outcomes include close friendships, social contacts, and group activities. Similarly, Spitzer29 recommended that quality of life or health measurement include the physical function, social function, emotional or mental state, burden of symptoms, and perceptions or sense of well being. Ferrans and Powers30 conceptualize Quality of Life as “satisfaction of the individual with areas of life that are important to that individual.” Therefore, in measuring quality of life outcome, it is important to include various dimensions. The National Heart Lung and Blood Institute31 (NHLBI) defined Health Quality of Life (HQL) as “a multidimensional concept referring to a person’s total well-being including his or her psychological, social and physical health status.” This conceptualization by the NHLBI was used as the definition of quality of life in this study. Therefore, outcomes affecting HQL were theorized to include the physical, social and psychological domains. The instruments used to measure these domains were the Quality of Life Index (QLI), Personal Resource Questionnaire (PRQ), Profile of Mood States (POMS), Symptom Scale (SS), Overall Health Rating Index
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(OHRI) and the Specific Activity Scale (SAS). The subscales of the QLI and POMS were separated to fit into each appropriate domain. Figure 1 illustrates the HQL model as described by the NHLBI with the physical, social and psychological domains and the instruments used to measure each domain.
METHOD Research design A prospective, longitudinal design was used in this study. In addition, subjects were matched on age (within 5 years) and on BSA (within 0.1 m2) as measured by the DuBois Body Surface Area Chart.32 BSA was chosen because several studies indicated it as significantly different in women compared with men.4,8,9 This is the first prospective study matching on these 2 variables. Approval was also obtained from the appropriate Institutional Review Boards.
Setting and sample This study was conducted in a 500-bed midwestern community hospital with an ongoing cardiothoracic surgical program. Potential subjects were identified from a CABS surgical schedule. The
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investigator first contacted hospitalized female patients in person to determine eligibility for participation. Upon admission to the study of a particular female subject, the investigator then sought a male patient to match the female counterpart in BSA and age. For all patients, consent was obtained after discussion about the purpose of the study. To ensure confidentiality, data were coded by subject number. Forty-eight women and 50 men were approached to participate in the study. Four women and 4 men declined to participate with no specific reason given. Of the 44 women who completed the preoperative questionnaire, 3 did not continue at the 1-month time period and 1 did not complete the 3-month questionnaire. The reason given by all women who chose not to continue in the study was that the questionnaire was too lengthy. Of the 46 men who completed the preoperative questionnaire, 1 died postoperatively, 4 did not complete the 1-month questionnaire, and 1 man did not complete the 3-month questionnaire because of its length. There was no difference in scores in these 5 men compared with the 40 who completed the study. The final sample consisted of 40 pairs of men and women scheduled to undergo first-time CABS who were matched for BSA and were within 5 years of each other in age. Patients undergoing valvular surgery, combination bypass grafts and valve replacement, or re-do CABS were not included in the study. All subjects were able to read and write in English.
Procedures and instrumentation The instruments for the study were formulated into a questionnaire booklet that was initially administered in an interview format. For the 1-month and 3-month follow-ups, questionnaires were mailed to each subject. One week before the mailing of the questionnaire, the investigator called each subject to remind them of their participation in the study and the need to again complete the questionnaire. A self-addressed stamped envelope was included for subjects to return the completed questionnaire to the investigator. A follow-up reminder phone call was made if the questionnaire had not been returned within 10 days of the mailing and another questionnaire was sent if necessary. Demographic/medical information sheet. The demographic/medical information sheet was used to collect data on sociodemographics, medical history, current medications, and laboratory and cardiac catheterization results.
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Quality of life index. The Ferrans and Powers30 QLI measures satisfaction with various aspects of life as well as importance of each of these aspects to the individual. The cardiac version of the QLI was used in this study. Both the satisfaction and the importance section contain 32 items that ask respondents to rate on a 6-point Likert scale ranging from 1 (very dissatisfied/unimportant) to 6 (very satisfied/important) and form the following 4 subscales: health and functioning, socioeconomic, psychological/spiritual, and family. The range of scores for each subscale is 0 to 30. Scores are calculated by weighting each satisfaction response with its paired importance response, summing this response, and dividing by the number of items answered. Content validity was established using the Content Validity Index.33 Construct validity was established with factor analysis and correlations with the Campbell, Converse and Rodgers measure of life satisfaction (r ⫽ .77; P ⬍ .05).34 Cronbach alphas for the cardiac version of the QLI were reported as 0.86 in angioplasty patients,35 0.98 in coronary bypass patients,36 and 0.92 in patients undergoing cardiac rehabilitation.37 Social support: personal resource questionnaire. The PRQ38 measures the following domains of social support: provision for attachment/intimacy; social integration; opportunity for nurturant behavior; reassurance of worth as an individual and in role accomplishments; and availability of informational, emotional, and material help. The PRQ is designed to be self-administered and contains 2 sections. The first section, which provides descriptive information, contains questions regarding situations in which respondents might need assistance and the quality and availability of that assistance. Section 2 is composed of 25 items that ask respondents to rate on a 7-point Likert scale ranging from 7 (strongly agree) to 1 (strongly disagree) how they feel about relationships with others and their ability to count on others for help and support. The items are then totaled with high scores indicating higher levels of perceived social support. Reliability estimates have been obtained with 4 different data sets. In a sample of 120 men and women, Cronbach alpha was reported at 0.93.39 The range of alphas for the 3 other samples (149 adult white middle-class spouses of persons with multiple sclerosis, 77 low-income mothers, and 94 couples expecting their first child) ranged from 0.88 to 0.90. Weinert38 reported further alphas ranging from 0.88 to 0.93. Construct validity was supported by significant positive correlations with the support subscale of the Cost and Reciprocity Index (r ⫽ .52;
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P ⬍ .001) and the Inventory of Socially Supported Behaviors (r ⫽ .40; P ⬍ .001).38 This instrument has not been used in the cardiac population. Profile of mood states. The POMS40 measures the following perceived affective mood states: tension/ anxiety; depression/dejection; anger/hostility; vigor/ activity; fatigue/inertia; and confusion/bewilderment. Subjects are given a list of 65 feelings and asked to rate how intensely they have experienced these feelings over the past week on a 5-point Likert scale from 0 (not at all) to 4 (extremely). A score is obtained for each mood factor by summing the responses for the adjectives that define each mood factor. Two adjectives, relaxed in the tension subscale and efficient in the confusion subscale are scored negatively. A total score is obtained by summing the scores on each individual mood factor except for vigor, which is weighted negatively. High scores indicate high levels of negative mood states whereas low scores indicate a low degree of negative mood states. The total score for the POMS can range from 0 to 168. The range of scores for each mood state is as follows: anger (0-48), confusion (0-28), depression (0-60), tension (0-36), fatigue (028), and vigor (0-32). The instrument is designed to be self-administered with scores obtained by summing the responses for each adjective associated with a particular mood state. Reliability and validity data have been well supported in the literature.41,42 Symptom scale. The SS43 assesses the patients’ level of angina, SOB, and fatigue and the extent to which these symptoms interfere with overall functional ability. Subjects first state whether they were or were not experiencing each individual symptom by responding yes or no. If they were experiencing the particular symptom, a summated rating scale is used to rate the frequency of the symptom, severity of the symptom, how easily the symptom occurs, the extent to which the symptom interferes with physical activity, and the method used to treat each symptom. Subscale scores are obtained by summing the responses for each individual symptom and a total score is calculated by summing each subscale score. If subjects do not experience a particular symptom, a zero is assigned. Initial testing of the instrument was obtained on patients undergoing a treadmill test. Cronbach alpha for the entire scale was 0.91. Cronbach alphas were also adequate for each subscale. Concurrent validity was determined by correlation with metabolic equivalent level achieved on the treadmill (r ⫽ .66; P ⬍ .01). Overall health rating index. The OHRI43 consists of 5 questions designed to measure subjects’ perception of their overall health and activity. Re-
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sponses are measured on a summated rating scale and are totaled to obtain an overall score. Subjects are asked to rank how they perceive their level of activity, their level of health, and the extent to which symptoms interfere with their activity and health. Scores can range from 6 to 36 with high scores indicating a high level of perceived health and activity and low scores indicating a low perception of health and activity. Testing of the instrument revealed an alpha coefficient of 0.87. Concurrent validity was established by adequate correlation (r ⫽ .45; P ⬍ .001) with results on a treadmill exercise test. It was expected that subjects who rated their overall health and activity level high would also perform well on the treadmill exercise test. Specific activity scale. The SAS44 measures the level of physical activity by having respondents select from a list of specific activities those which they are able to perform without symptoms of chest pain, fatigue or SOB. The specific activities have corresponding metabolic equivalents and the respondents can be placed in a functional classification from I to IV based upon the associated MET guidelines assigned to each classification level (I ⫽ ⬎ 7 METs; II ⫽ 5-7 METs; III ⫽ 2-5 METS; and IV ⬍ 2 METs). Reliability of the SAS was determined by inter-rater reliability (2 ⫽ 6.85; P ⬍ .05) by having separate raters place respondents in the appropriate functional classification. Validity was determined by comparison of MET level achieved on the treadmill exercise test with MET level identified on the SAS (2 ⫽ 8.65; P ⫽ .013). Activities and their corresponding MET levels, which are more specific for women, were added to the original questionnaire for this study. Among these were gardening (5.0 METs), ironing (2.3 METs), moving furniture (5 METs), and putting away groceries (2.5 METs). In addition, MET levels assigned to each activity were summed and then averaged to obtain a specific mean MET level for each subject instead of using the classification scheme designed by the authors.
HYPOTHESIS The following research hypotheses were tested: 1. There will be differences between men and women matched on age within 5 years and BSA on the perceived physical domain of HQL at the preoperative, 1-month postoperative, and 3-month postoperative time periods. 2. There will be differences between men and women matched on age within 5 years and BSA on the perceived social domain of HQL at the
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preoperative, 1-month postoperative, and 3-month postoperative time periods. 3. There will be differences between men and women matched on age within 5 years and BSA on the perceived psychological domain of HQL at the preoperative, 1-month postoperative, and 3-month postoperative time periods.
DATA ANALYSIS Data were coded and analyzed using SPSS software version 8.0.45 Descriptive statistics were generated for sociodemographic information obtained as well as the QLI, the POMS, the PRQ, the OHRI and the SS for the sample as a whole and individually for both men and women. To determine presence of significant differences in the QLI, the POMS, the PRQ, the SS, and the OHRI between and within the groups of men and women preoperatively and at one month and three months postoperatively, a repeated measures ANOVA was performed. When significant F tests were found, post-hoc tests using the Bonferonni correction were used to determine where differences between genders occurred at the 3 respective time periods.46 An Analysis of Covariance (ANCOVA) was used if there were significant differences on the preoperative variables to control for those differences.
RESULTS Sample characteristics The sample consisted of 40 pairs of men and women matched on age within 5 years and BSA. All subjects were Caucasian. The mean age of women was 62.7 (SD ⫽ 12.1) years compared with 63.8 (SD ⫽ 10.8) years for men [t(79) ⫽ .37, P ⬎ .7]. The mean BSA was 1.8 (SD ⫽ 0.19) for women and 1.9 (SD ⫽ 0.19) for men [t(79)⫽ –1.82, P ⬎ .07]. The majority of both men (85%, n ⫽ 34) and women (75%, n ⫽ 30) were married. The mean years of school attended by women were 11.6 (SD ⫽ 2.2) compared with 12.2 (SD ⫽ 3.0) for men. The majority of women (80%, n ⫽ 32) and men (65%, n ⫽ 26) reported an annual income of less than $30,000. The majority of both women (95%, n ⫽ 38) and men (98%, n ⫽ 39) were either on Medicare, had private insurance or a combination of each.
Medical/physiologic data Medical data revealed a family history of heart disease was reported by 85% (n ⫽ 34) of women and 89% (n⫽ 35) of men. Thirty-eight percent of women (n ⫽ 15) and 20% of men (n ⫽ 8) were diabetic.
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Hypertension was present in 72% (n ⫽ 28) of the women and 58% (n ⫽ 23) of the men (2 ⫽ 1.07; df ⫽ 1; P ⬎ .28). Thirty-three percent (n ⫽ 12) of women had suffered a myocardial infarction before surgery compared with 58% (n ⫽ 23) of men (2 ⫽ 2.0; df ⫽ 1; P ⬎ .15). The majority of women (92%, n ⫽ 36) were postmenopausal, less than half of the women (36%, n ⫽ 14) reported ever using birth control pills, and less than half of the women (28%, n ⫽ 11) reported ever taking a hormone replacement. Women underwent a mean of 2.8 (SD ⫽ 0.8) bypass grafts compared with 3.2 (SD⫽ 0.9) for men. The number of bypass grafts was significantly lower in women [t(78) ⫽ –1.98; P ⫽ .05]. Analysis of laboratory data revealed no significant differences between women and men in serum glucose levels, blood urea nitrogen levels, serum creatinine levels, and triglyceride levels. Serum cholesterol levels were significantly higher in women (F ⫽ 211.3 ⫾ 44.6) than men (M ⫽ 178 ⫾ 33.4) preoperatively [t(78) ⫽ 3.09; P ⫽ .003].
Hypothesis 1: physical domain of HQL The first research hypothesis, regarding the perceived physical domain of HQL at the preoperative, 1-month postoperative, and 3-month postoperative time periods was accepted (Table I). Although improvements were seen for both women and men at both postoperative time periods, women did not respond as favorably on the outcomes measured when compared with men. Women reported significantly higher levels of total symptoms preoperatively compared with men. The total scores on the SS significantly decreased for both women and men at the 1-month and 3-month time periods compared with the preoperative time period. There were no differences in scores on the angina subscale between women and men and there were no differences in the numbers of women reporting experiencing angina at each time period compared with men (Table II).Women reported higher levels of SOB at all 3 times periods compared with men and significantly more women reported experiencing SOB at the preoperative and 1-month postoperative time periods compared with men (Table II). When controlling for the difference between women and men at the preoperative time period, women still reported significantly higher levels of SOB at 1 month postoperatively and 3 months postoperatively compared with men. There were no differences on the fatigue subscale of the SS on both the reported
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Table I Physical domain
Women (n ⴝ 40) Scale (Possible score)
Symptom Scale (0-81) Angina subscale (028) Shortness of breath subscale (028) Fatigue subscale (025) Health subscale QLI (0-30) MET average (0-8) Fatigue-POMS (0-28) Vigor -POMS (0-32) Overall Health Rating Index (6-36)
Preop
1 month
3 month
X (SD) 143.1 (24.6) 12. (11.4)
X (SD) 22.3 (11) 1.8 (4.5)
X (SD) 20.5 (15.8) 3.5 (6.4)
Within Women F statistic
42.1* 23.0*
Men (n ⴝ 40) Preop
1 month
3 month
X (SD) 34.4 (18.4) 11.2 (8.9)
X (SD) 14.9 (8.8) 1.7 (4.8)
X (SD) 15.8 (13.1) 3.1 (6.3)
Within Men
Between gender groups
F statistic
F statistic
61.3*
6.2*
36.2*
0.14
14 8.4 (10.7) 8.1)
7.2 (9.1)
13.8*
8.9 (9.7)
3 (6.0)
3.3 (6.6)
12.9*
16.9*
16.7 (6.0)
12 (4)
10.8 (6.5)
34.2*
14.7 (5.8)
10.2 (5.9)
11.5 (5.2)
24.0*
1.3
18.9 (5.1) 3 (0.63) 13.3 (7) 11.6 (5.8) 21 (6)
21.5 (3.9) 3.7 (0.46) 7.3 (5.6) 15.8 (6.9) 23.2 (4.8)
21.5 (5.2) 3.3 (.28) 7 (5.7) 15.9 (7.6) 22.9 (5.2)
7.2*
21.4 (4) 3.9 (0.41) 11.7 (4.9) 13.6 (6.7) 25.4 (4.4)
24.3 (2.6) 3.7 (.46) 6.3 (3.7) 20.2 (5.6) 27.7 (4.4)
25 (2.3) 3.8 (0.3) 5.5 (3.7) 21.3 (5.7) 27.74 (3.7)
49.9*
14.6*
2.8
7.4*
64.5*
2.5
41.5*
11.1*
6.8*
29.8*
10.5* 31.9* 12.8* 2.4
*P ⬍ .01 Note: An alpha of .01 was set for post hoc tests using the Bonferroni correction.
scores or in the numbers of women and men reporting feeling fatigued at each time period (Table 2). In addition, on the fatigue subscale off the POMS, there were no differences between women and men at any time period. The amount of perceived fatigue on the POMS subscale and the fatigue subscale of the SS did decrease significantly for both women and men at 1 and 3 months postoperatively compared with the preoperative time period. On the total QLI, women reported a statistically lower level of quality of life compared with men (F ⫽ 29.9, P ⬍ .001). Preoperatively, women reported a mean score of 20.9 (SD ⫽ 4.6) compared with 23.3 (SD ⫽ 3.2) for men. At 1 month postoperatively, women reported a mean score of 22.8 (SD ⫽ 4.0) compared with 24.6 (SD ⫽ 2.7) for men. Lastly, at
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the 3-month postoperative time period, women reported a mean score of 22.8 (SD ⫽ 4.6) compared with 25.7 (SD ⫽ 1.8) for men. Women reported a significantly lower quality of life on the health and functioning subscale of the QLI compared with men at each time period. When controlling for the differences preoperatively, women continued to report lower levels of HQL at both 1 month and 3 months postoperatively compared with men. For both women and men, scores on this subscale significantly improved at the postoperative time periods compared with the preoperative time period. In terms of activity, women reported lower mean MET levels compared with men preoperatively. When controlling for the differences preoperatively,
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Table II Numbers (percentages) of subjects reporting symptoms at each time period One month postoperatively
Preoperatively
Angina SOBa,b Fatigue
Three months postoperatively
Women n (%)
Men n (%)
Women n (%)
Men n (%)
Women n (%)
Men n (%)
25 (63%) 30 (73%) 39 (97%)
26 (65%) 20 (50%) 37 (92%)
6 (15%) 23 (58%) 39 (97%)
5 (12%) 8 (20%) 27 (67%)
11 (27%) 18 (45%) 34 (85%)
12 (30%) 12 (30%) 36 (90%)
a ⫽ Preoperatively X2(1) ⫽ 3.67; P ⫽ .05; b ⫽ One month postoperatively X2(1) ⫽ 4.99; P ⬍ .05.
women continued to report significantly lower mean MET levels at 3 months postoperatively compared with men. Whereas mean MET levels for men were unchanged across the time periods, mean MET levels at the 1-month time period were significantly higher than the preoperative time period in women. Though mean MET levels in women were also higher at the 3-month time period compared with the preoperative time period, they were not statistically significant. On the vigor subscale of the POMS, women reported significantly less vigor compared with men at both postoperative time periods. Vigor scores did significantly improve for both women and men at the 1 and 3-month postoperative time periods compared with the preoperative time period. Lastly, on rating their overall health, women reported significantly lower levels of perceived health at all 3 time periods compared with men. When controlling for the differences preoperatively, women continued to report lower levels of perceived health and activity at 1 and 3-months postoperatively compared with men. There were no changes in perceived level of health for women across the time periods, whereas men reported significantly increased levels of perceived health at the 1 and 3-month postoperative time periods compared with the preoperative time period.
Hypothesis 2: social domain of HQL The second research hypothesis, regarding the perceived social domain of HQL at the preoperative, 1-month postoperative, and 3-month postoperative time periods was also accepted (Table III).Women reported lower levels of social support on the socioeconomic subscale of the QLI at the 3-month
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postoperative time period compared with men. Scores for women remained unchanged on this subscale whereas men reported significantly higher quality of life on the socioeconomic subscale at the 3-month time period compared with the preoperative time period. There were no differences found on the family subscale of the QLI between women and men across the time periods. Women reported significantly higher family quality of life at the 1-month and three-month postoperative time periods compared with the preoperative time period. There was no change in scores for men across the time periods. There were no differences on the PRQ between women and men across the time periods. Scores for both women and men were unchanged across the 3 time periods.
Hypothesis 3: psychological domain of HQL The third research hypothesis, regarding the perceived psychological domain of HQL at the preoperative, 1-month postoperative, and three-month postoperative time periods was also accepted (Table IV).On the psychological subscale of the QLI, women reported significantly lower levels of psychological quality of life compared with men at the preoperative time periods. After controlling for the preoperative difference, there were no differences in scores at the 1-month time period, however, women scored significantly lower at the 3-month time period. Mean scores for both women and men were unchanged across the 3 time periods.
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Table III Social domain
Women (n ⴝ 40) Scale (Possible score)
Family subscale QLI (0-30) Personal Resource Questionnaire (25-245) Socio-economic subscale QLI (0-30)
Preop
1 month
3 month
X (SD) 22.8 (5.2) 140 (19.9)
X (SD) 25 (6.0) 142.2 (17.3)
X (SD) 25.9 (4.2) 141 (17.3)
23.2 (4.5)
23.8 (4.8)
23.5 (4.6)
Within Women F statistic
22.0* 0.042
0.27
Men (n ⴝ 40) Preop
1 month
3 month
X (SD) 25.8 (5.0) 145 (27.2)
X (SD) 26 (4.1) 141 (17.3)
X (SD) 26.8 (3.9) 139 (19.1)
24.5 (4.7)
24.9 (3.1)
26.2 (2.1)
Within Men
Between gender groups
F statistic
F statistic
2.0
3.5
1.1
0.04
5.1*
4.4*
*p ⬍ .01 Note: An alpha of .01 was set for post hoc tests using the Bonferroni correction.
On the POMS, women reported greater negative mood states at the 1-month and 3-month postoperative time periods compared with men. There were no differences at the preoperative time period. For both women and men, mean scores on the POMS significantly decreased at the 1-month and 3-month time periods compared with the preoperative time period. Examining the subscales of the POMS, there were no differences in anger, confusion and tension scores between women and men. Women reported no changes on the anger subscale at each time period whereas men reported significantly lower levels of anger at the 1-month and three-month postoperative time periods compared with the preoperative time period. Both women and men reported significantly less tension and confusion at the 1-month and 3-month postoperative time periods compared with the preoperative time period. On the depression subscale of the POMS, women reported significantly higher levels of depression at the preoperative time period. After controlling for this difference, there were no differences in reported levels of depression at the 1-month and 3-month time periods.
DISCUSSION The results of this study support results found in the literature that women do not have as favorable
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outcomes after CABS as men, particularly on the physical outcomes. The study adds to the current body of knowledge by controlling for age and body size and focusing on gender differences in quality of life before and after surgery. Both women and men did experience symptom relief after CABS. The majority of both women and men reported being free of angina after CABS, a finding that is supported with results found in published literature.9,15,19,47 Women continued to report feeling SOB in higher amounts compared with men postoperatively. Sjoland19 also reported significantly fewer women than men reported freedom from SOB 2 years after CABS. In this study, women received significantly lower numbers of bypass grafts compared with men, perhaps resulting in incomplete revascularization in women. The reason why women received fewer grafts is unknown. This may account for the continued SOB experienced by women. Women did report being able to perform activities at a higher mean MET levels at 1 and 3 months postoperatively indicating they were doing more activities after surgery compared with preoperatively whereas mean MET levels for men remained fairly constant. This increase in activity may also account for the continued feelings of SOB reported by women. Physical quality of life was poorer in women across the time periods as were overall perceptions of health. Physical quality of life included ratings of health on the
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Table IV Psychological domain
Scale (Possible score)
Psychological/ spiritual subscale QLI (0-30) Profile Of Mood States (0-168) Anger (0-48) Confusion (0-28) Depression (0-60) Tension (0-36)
Women (n ⴝ 40) Preop
1 month
3 month
X (SD) 122.1 (6)
X (SD) 23.4 (5.5)
X (SD) 22.9 (5.8)
48.5 (31.5)
19.4 (27.6)
20.6 (30.5)
6.5 (6.7) 8.3 (4.8) 15.4 (11.5) 15.7 (6.1)
4.9 (5.1) 6 (3.4) 8 (9.3) 9.9 (5.3)
4.6 (5.3) 6.3 (3.5) 8.4 (10) 9.1 (4.9)
Within Women F statistic
Men (n ⴝ 40) Preop
1 month
3 month
X (SD) 25.2 (4.5)
X (SD) 25.4 (3.2)
X (SD) 26.2 (2.8)
38.6*
40.4 (26.5)
9.6 (17.4)
3.3
8.1 (6.6) 9.2 (3.9) 10.9 (8.4) 14.5 (6.2)
3.1 (3.2) 5.7 (2.5) 4.6 (5.7) 9.8 (4.5)
1.9
9.1* 24.5* 50.6*
Within Men
Between gender groups
F statistic
F statistic
3.2
3.8*
8.9 (20.1)
49.3*
3.8*
4.1 (4.6) 5.8 (2.8) 5.6 (6.4) 9.1 (4.7)
10.0*
0.08
24.1*
0.02
13.4*
4.2*
40.3*
0.20
*P ⬍ .01 Note: An alpha of .01 was set for post hoc tests using the Bonferroni correction.
QLI, amount of SOB experienced, ability to perform activities of higher MET levels, levels of vigor and fatigue, and overall rating of health. In addition, women reported a lower quality of life on the total QLI. Since there were no differences found between women and men in terms of medical history, why women rated their physical and overall quality of life and overall health lower than men at the preoperative time period is unknown. Similarly, King47 found women reported lower quality of life scores compared with men preoperatively and at 1, 2 and 3 months postoperatively. Postoperatively, the higher level of symptoms, particularly SOB, may contribute to the lower ratings of HQL and overall health ratings seen in this study. Of significance are the higher levels of depression reported by women compared with men preoperatively. In this study, the level of depression reported by women is higher than scores reported on the depression subscale of the POMS in other studies. Czajkowski21 reported women, before surgery surgery,
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scored above a threshold score used to screen for clinical depression. The higher level of symptoms, lower levels of vigor, and lower perceived health ratings on the QLI could contribute to the higher depression ratings of women. Other authors51 also found women reported significantly more depressive symptoms compared with men and the depressive symptoms were correlated positively with pain. Because only 1 of the social support outcomes showed significance, no conclusions can be drawn about the possible impact of social support on the mood ratings of the women and men. In this study the majority of women and men were married, which may account for similar reportings of perceived social support. Overall, women in this study seemed to perceive that they experienced poorer outcomes after CABS compared with men preoperatively and at both the 1-month and three-month postoperative periods. The women reported lower levels of activity, vigor, and overall health rating and higher levels of SOB and depression.
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LIMITATIONS In this study it was difficult to obtain a male subject match for women on BSA. Several studies have reported women subjects had a smaller BSA than men.6 Loop11 reported a mean BSA for women of 1.66 compared with 1.92 for men. Similarly, Khan10 reported a mean BSA of 1.7 for women compared with 1.9 for men. A BSA of 1.8 would be equivalent to a person who is 5 feet 5 inches tall and 160 pounds. A person who is 5 feet 10 inches tall and 180 pounds would have a BSA of 2.0. The higher BSA in women in the current study was needed to find a match with available male subjects who generally have a higher BSA. To be able to find a match with a man, women with a BSA of 1.7 or above only were asked to participate in the present study resulting in a mean BSA of 1.8 for the female subjects. This is somewhat higher than reported in other studies and limits the generalizability of the results of the study to women with a BSA of 1.8 or above. The sample was homogeneous in regards to race. All subjects were Caucasian. Although efforts were made to include minorities in the sample, there were no minorities that fit the inclusion criteria available to participate in the study. Consequently, the results of the study are not generalizeable to all races. By study design, subjects were enrolled in the study as they were scheduled to undergo CABS so that the preoperative data could be obtained. Subjects who underwent emergent bypass surgery were eliminated from participation because the preoperative data would be difficult to obtain. Studies have shown differences between women and men in outcomes after CABS under emergent circumstances.50,51 The exclusion of subjects who underwent emergent CABS may have limited the differences found between women and men in the present study.
SUGGESTIONS FOR FURTHER RESEARCH Clearly, more prospective studies that examine differences between women and men are needed to validate our results. Studies need to include women of smaller size as well as men of larger size to determine if BSA is a factor in outcomes between women and men. Also, studies are needed which include subjects with more comorbid conditions undergoing CABS. Lastly, studies need to include minorities to understand outcomes after CABS and identify potential differences based not only on gender, but also
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on ethnicity. [The subjects in this study represent a relatively healthy population that may have accounted for the favorable outcomes seen postoperatively].
REFERENCES 1. American Heart Association. The 1999 Heart and stroke statistical update. Dallas: American Heart Association; 1998. 2. The Society of Thoracic Surgeons. Data analysis of the society of thoracic surgeons; 1991. 3. Bolooki H, Vargas A, Green R, Kaiser GA, Ghahramani A. Results of direct coronary artery surgery in women. J Thorac Cardiovasc Surg 1975;69(2):271-7. 4. Gardner TJ, Horneffer PJ, Gott VL, Watkins L Jr, Baumgartner WA, Borkon AM, Reitz BA. Coronary artery bypass grafting in women. A ten-year perspective. Ann Surg 1985;201(6):780-4. 5. Golding LR, Groves LK. Results of coronary artery surgery in women. Cleve Clin Q 1976;43(3):113-5. 6. Hannan EL, Bernard HR, Kilburn HC, O’Donnell JF. Gender differences in mortality rates for coronary artery bypass surgery. Am Heart J 1992;123(4 Pt 1):866-72. 7. Jamieson WR, Miyagishima RT. Aortocoronary bypass surgery in women. Can J Surg 1979;22(2):132-4. 8. Khan SS, Nessim S, Gray R, Czer LS, Chaux A, Matloff J. Increased mortality of women in coronary artery bypass surgery: evidence for referral bias. Ann Intern Med 1990; 112(8):561-7. 9. Loop FD, Golding LR, MacMillan JP, Cosgrove DM, Lytle W, Sheldon WC. Coronary artery surgery in women compared with men: analysis of risks and long-term results. J Am Coll Cardiol 1983;1:383-90. 10. Richardson JV, Cyrus RJ. Reduced efficacy of coronary artery bypass grafting in women. Ann Thorac Surg 1986;42(6 Suppl): S16-21. 11. Edwards FH, Carey JS, Grover FL, Bero JW, Hartz RS. Impact of gender on coronary bypass operative mortality. Ann Thorac Surg 1998;66(1):125-31. 12. Douglas JS Jr, King SB 3rd, Jones EL, Craver JM, Bradford JM, Hatcher CR Jr. Reduced efficacy of coronary bypass surgery in women. Circulation 1981;64(2 Pt 2):II11-6. 13. Eaker ED, Kronmal R, Kennedy JW, Davis K. Comparison of the long-term, postsurgical survival of women and men in the Coronary Artery Surgery Study (CASS). Am Heart J 1989; 117(1):71-81. 14. Killen DA, Reed WA, Arnold M, McCallister BD, Bell HH. Coronary artery bypass in women: long-term survival. Ann Thorac Surg 1982;34(5):559-63. 15. Golino A, Panza A, Jannelli G, Vigorito C, Giordano A, Persico S, et al. Myocardial revascularization in women. Tex Heart Inst J 1991;18:194-8. 16. Jeffery DL, Vijayanagar RR, Bognolo DA, Eckstein PF. Results of coronary bypass surgery in elderly women. Ann Thorac Surg 1986;42(5):550-3. 17. Tyras DH, Barner HB, Kaiser GC, Codd JE, Laks H, Willman VL. Myocardial revascularization in women. Ann Thorac Surg 1978;25(5):449-53. 18. Rahimtoola SH, Bennett AJ, Grunkemeier GL, Block P, Starr A. Survival at 15 to 18 years after coronary bypass surgery for angina in women. Circulation 1993;88(5 Pt 2):II71-8. 19. Sjoland H, Caidahl K, Karlson BW, Karlsson T, Herlitz J. Limitation of physical activity, dyspnea and chest pain before and two years after coronary artery bypass grafting in relation to sex. Int J Cardiol 1997;61(2):123-33. 20. Sjoland H, Wiklund I, Caidahl K, Haglid M, Westberg S, Herlitz J. Improvement in quality of life and exercise capacity after coronary bypass surgery. Arch Intern Med 1996;156(3): 265-71.
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21. Czajkowski SM, Terrin M, Lindquist R, Hoogwerf B, Dupuis G, Shumaker SA, Gray JR, Herd JA, Treat-Jacobson D, Zyzanski S, Knatterud GL. Comparison of preoperative characteristics of men and women undergoing coronary artery bypass grafting (the Post Coronary Artery Bypass Graft [CABG] Biobehavioral Study). Am J Cardiol 1997;79(8):1017-24. 22. Zyzanski SJ, Rouse BA, Stanton BA, Jenkins CD. Employment changes among patients following coronary bypass surgery: social, medical, and psychological correlates. Public Health Rep 1982;97(6):558-65. 23. Sokol RS, Folks DG, Herrick RW, Freeman AM 3rd. Psychiatric outcome in men and women after coronary bypass surgery. Psychosomatics 1987;28(1):11-6. 24. Ross AC, Ostrow L. Subjectively perceived quality of life after coronary artery bypass surgery. Am J Crit Care 2001;10(1): 11-6. 25. Hunt JO, Hendrata MV, Myles PS. Quality of life 12 months after coronary artery bypass graft surgery. Heart Lung 2000; 29(6):401-11. 26. Karlsson I, Berglin E, Larsson PA. Sense of coherence: quality of life before and after coronary artery bypass surgery—a longitudinal study. J Adv Nurs 2000;31(6):1383-92. 27. Luquire, R. Gender differences in quality of life in coronary artery bypass graft patients at one, three and six months. Unpublished dissertation. Texas Women’s University. 1997. 28. Ware JE Jr. Conceptualizing and measuring generic health outcomes. Cancer 1991;67(3 Suppl):774-9. 29. Spitzer WO. State of science 1986: quality of life and functional status as target variables for research. J Chronic Dis 1987;40(6):465-71. 30. Ferrans CE, Powers MJ. Quality of life index: development and psychometric properties. ANS Adv Nurs Sci 1985;8(1):1524. 31. Schron EB, Shumaker SA. The integration of health quality of life in clinical research: experiences from cardiovascular clinical trials. Prog Cardiovasc Nurs 1992;7(1):21-8. 32. Dubois EF. Basal metabolism in health and disease. Philadelphia: Lea and Febiger; 1936. 33. Oleson M. Content validity of the quality of life index. Appl Nurs Res 1990;3(3):126-7. 34. Ferrans CE, Powers MJ. Psychometric assessment of the Quality of Life Index. Res Nurs Health 1992;15(1):29-38. 35. Bliley AV, Ferrans CE. Quality of life after coronary angioplasty. Heart Lung 1993;22(3):193-9. 36. Papadantonaki A, Stotts NA, Paul SM. Comparison of quality of life before and after coronary artery bypass surgery and
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37. 38.
39. 40. 41. 42. 43. 44.
45. 46. 47. 48. 49. 50. 51.
percutaneous transluminal angioplasty. Heart Lung 1994; 23(1):45-52. Deshotels A, Planchock N, Dech Z, Prevost S. Gender differences in perceptions of quality of life in cardiac rehabilitation patients. J Cardiopulm Rehabil 1995;15(2):143-8. Weinert C. Measuring Social Support: revision and further development of the personal resource questionnaire. In: Waltz C, Strickland O, eds. Measurement of nursing outcomes. volume I: measuring client outcomes. New York: Springer Publishing Company; 1988. Weinert C, Brandt PA. Measuring social support with the Personal Resource Questionnaire. West J Nurs Res 1987;9(4): 589-602. McNair D, Lorr M, Droppleman L. EITS manual for the profile of mood states. San Diego: Educational and industrial testing service; 1971. Lorr M, Daston P, Smith IR. An analysis of mood states. Educ Psychol Meas 1967;27:89-86. McNair D, Lorr M. An analysis of mood in neurotics. J Abnorm Soc Psychol 1964;69:620-7. Keresztes P, Penckofer S, Holm K, Merritt S. Measurements of functional ability in patients with coronary artery disease. J Nurs Meas 1993;1:19-28. Goldman L, Hashimoto B, Cook EF, Loscalzo A. Comparative reproducibility and validity of systems for assessing cardiovascular functional class: advantages of a new specific activity scale. Circulation 1981;64(6):1227-34. Norusis M. SPSS for windows: advanced statistics. Chicago: SPSS Inc; 1993. Sokol R, Rohlf F. Biometry. New York: WH Freeman; 1981. King KB, Reis HT, Porter LA, Norsen LH. Social support and long-term recovery from coronary artery surgery: effects on patients and spouses. Health Psychol 1993;12(1):56-63. King KM. Gender and short-term recovery from cardiac surgery. Nurs Res 2000;49(1):29-36. Con AH, Linden W, Thompson JM, Ignaszewski A. The psychology of men and women recovering from coronary artery bypass surgery. J Cardiopulm Rehabil 1999;19(3):152-61. Hannan EL, Bernard HR, Kilburn HC Jr, O’Donnell JF. Gender differences in mortality rates for coronary artery bypass surgery. Am Heart J 1992;123(4 Pt 1):866-72. Weintraub WS, Wenger NK, Jones EL, Craver JM, Guyton RA. Changing clinical characteristics of coronary surgery patients. Differences between men and women. Circulation 1993;88(5 Pt 2):II79-86.
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OBJECTIVE: The primary purpose of this study was to examine differences between women and men on physical, social and psychological domains of health quality of life before, 1 month after, and 3 months after coronary artery bypass surgery. DESIGN: A prospective, longitudinal design was used. SETTING: The study was conducted at a Midwestern, 500-bed community hospital with an ongoing cardiothoracic surgical program. PARTICIPANTS: Forty pairs of women and men matched on age within 5 years and body surface area within 0.1m2. INSTRUMENTS: The physical, social and psychological domains of health quality of life were assessed using the following instruments: Ferrans and Powers Quality of Life Index, Specific Activity Scale, Symptom Scale, Profile of Mood States, Overall Health Rating Index, and Personal Resource Questionnaire. RESULTS: Both women and men improved on physical and psychological measures following coronary artery bypass surgery. Compared with men, women reported more shortness of breath and depression and lower ratings of activity, vigor, and overall health. Measures of social support yielded little information. CONCLUSIONS: Despite matching for age and body surface area, women did not have as favorable an outcome after surgery as men. Continued research needs to further examine the interaction of physical outcomes and depression in women after coronary artery bypass surgery. (Heart Lung® 2003;32:308-19.)
INTRODUCTION Fifty-eight million people in the United States, or 1 in 5, suffer some form of cardiovascular disease, the number 1 killer of both men and women1. Cardiovascular disease claims the lives of more than 500,000 women every year. Data obtained from The Society of Thoracic Surgeons2 revealed that the number of women undergoing coronary artery bypass surgery (CABS) is gradually increasing. Studies on outcomes in patients after CABS have examined both physical outcomes (such as operative mortality, symptom relief, graft patency rates, functional From the aPurdue University Calumet, Hammond, Indiana, bUniversity of Illinois at Chicago, Chicago, Illinois, cDePaul University, Chicago, Illinois, dLoyola University, Chicago, Illinois, USA. Reprint requests: Patricia A. Keresztes, PhD, RN, CCRN, 606 Chauncey Court, Mishawaka, IN 46545. Copyright © 2003 by Mosby, Inc. 0147-9563/2003/$30.00 ⫹ 0 doi:10.1016/S0147-9563(03)00101-8
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status, and return to work) and psychosocial outcomes. The results of many studies cited in the literature review section indicated that women do not have as favorable outcomes after CABS as men.
PURPOSE The purpose of this study was to determine if there were differences between men and women undergoing CABS matched on body surface area (BSA) (within 0.1 m2) and age (within 5 years) on the physical, social and psychological domains of health quality of life (HQL). Observations were made immediately before surgery, at 1 month postoperatively, and at 3 months postoperatively.
LITERATURE REVIEW The literature is replete with studies comparing the outcomes of women and men undergoing CABS. Though the majority of these studies does not spe-
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cifically focus on quality of life, it does examine various dimensions included in the conceptualization of quality of life. Physical outcomes studied include mortality, relief of symptoms of angina, shortness of breath (SOB) and fatigue, and exercise capacity. Several studies reported women have a higher operative mortality after CABS,3-11 whereas other studies found no differences in operative mortality between genders. 12-16 Various hypotheses accounted for the differences in operative mortality found between men and women. These include that women had smaller coronary artery size, had poorer revascularization, had smaller body size as measured by BSA, had increased rates of diabetes mellitus and congestive heart failure preoperatively, and were older.7-10,12,15,17 Several studies showed that, in addition to an having an increase in operative mortality, women do not experience the same level of symptom relief as men postoperatively.18,19,20 Rahimtoola and colleagues18 reported that women had a lower incidence of being angina free after surgery compared with men. Sjoland19 found significantly more men than women reported being free from SOB 2 years after CABS. These authors also found women reported a higher frequency of chest pain compared with men at both 3 months and 2 years after CABS. Sjoland20 reported that men performed better on, along with mortality and symptom relief, exercise tests both preoperatively and at 2 years postoperatively. The improvement in exercise capacity between the 2 time periods was also greater in men than women. Other investigators21 reported that women had less favorable physical functioning and ability to carry out activities of daily living compared with men before surgery. Therefore, on many measures of physical outcome after CABS women have been shown to have poorer outcomes than men. The psychosocial aspect of quality of life in patients undergoing CABS has also been reported in the literature. Psychosocial outcomes studied include depression and work status. Consistent with physical outcomes after CABS, psychosocial outcomes studied revealed that women do not fare as well as men after CABS. One study specific to gender differences after CABS found that fewer women than men returned to work at all postoperatively, and women who did resume employment took an average of 1 month longer to return to work.22 Others reported both more preoperative and more postoperative depression in women compared with men.21,23 Few studies have focused on gender differences in quality of life after CABS. The studies specific to
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quality of life after CABS are prospective studies that include the physical, social, and psychological dimensions of quality of life. However, there is a paucity of studies that address gender differences in the measurement of quality of life before and after CABS. Three recent studies specific to quality of life all reported improvements in quality of life measures after CABS.24-26 Ross and Ostrow24 measured mood states using the Profile of Mood States (POMS) and quality of life using the Quality of Life Index (QLI) in subjects before CABS, 6 weeks after CABS, and 3 months after CABS. The authors reported that, after CABS, subjects’ perceptions of mood states, physical and social functioning, and quality of life improved compared with perceptions before surgery. There was no report of gender differences. In addition, Hunt et al25 reported significant improvements in quality of life measures 12 months after CABS. Quality of life measures included physical functioning, social functioning, and pain. Once again there was no report of gender differences. Lastly, Karlsson et al26 reported improvements in the quality of life measures of depressed mood states, stress, and anxiety after CABS with no references to gender differences. Specific to gender differences in quality of life after CABS, Luquire27 examined 49 female subjects and 80 male subjects at 3 and 6 months postoperatively. Subjects were not measured preoperatively. The author found that women reported more severe cardiac symptoms, however there were no differences in reported quality of life between women and men at either time period. The literature review reveals disparate findings regarding outcomes of women compared with men after CABS. Many studies have been retrospective in nature and few prospective studies have focused on gender differences in quality of life after CABS. In addition, many factors have been hypothesized to account for poorer outcomes in women. Two of these, age and BSA, have been controlled in the study. This study is intended to address this gap in the literature by controlling for age and body size and focusing on gender differences specific to quality of life before and after CABS.
CONCEPTUAL FRAMEWORK In conceptualizing disease impact and treatment outcomes, Ware28 advocated the measurement of physical, mental, and social health and well being. Physical measures include personal functioning, role functions, disability, and self-rating of health and physical symptoms. Mental outcomes include
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Fig 1 Health Quality of Life (HQL).
positive affect, psychological distress, and psychosomatic symptoms. Social outcomes include close friendships, social contacts, and group activities. Similarly, Spitzer29 recommended that quality of life or health measurement include the physical function, social function, emotional or mental state, burden of symptoms, and perceptions or sense of well being. Ferrans and Powers30 conceptualize Quality of Life as “satisfaction of the individual with areas of life that are important to that individual.” Therefore, in measuring quality of life outcome, it is important to include various dimensions. The National Heart Lung and Blood Institute31 (NHLBI) defined Health Quality of Life (HQL) as “a multidimensional concept referring to a person’s total well-being including his or her psychological, social and physical health status.” This conceptualization by the NHLBI was used as the definition of quality of life in this study. Therefore, outcomes affecting HQL were theorized to include the physical, social and psychological domains. The instruments used to measure these domains were the Quality of Life Index (QLI), Personal Resource Questionnaire (PRQ), Profile of Mood States (POMS), Symptom Scale (SS), Overall Health Rating Index
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(OHRI) and the Specific Activity Scale (SAS). The subscales of the QLI and POMS were separated to fit into each appropriate domain. Figure 1 illustrates the HQL model as described by the NHLBI with the physical, social and psychological domains and the instruments used to measure each domain.
METHOD Research design A prospective, longitudinal design was used in this study. In addition, subjects were matched on age (within 5 years) and on BSA (within 0.1 m2) as measured by the DuBois Body Surface Area Chart.32 BSA was chosen because several studies indicated it as significantly different in women compared with men.4,8,9 This is the first prospective study matching on these 2 variables. Approval was also obtained from the appropriate Institutional Review Boards.
Setting and sample This study was conducted in a 500-bed midwestern community hospital with an ongoing cardiothoracic surgical program. Potential subjects were identified from a CABS surgical schedule. The
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investigator first contacted hospitalized female patients in person to determine eligibility for participation. Upon admission to the study of a particular female subject, the investigator then sought a male patient to match the female counterpart in BSA and age. For all patients, consent was obtained after discussion about the purpose of the study. To ensure confidentiality, data were coded by subject number. Forty-eight women and 50 men were approached to participate in the study. Four women and 4 men declined to participate with no specific reason given. Of the 44 women who completed the preoperative questionnaire, 3 did not continue at the 1-month time period and 1 did not complete the 3-month questionnaire. The reason given by all women who chose not to continue in the study was that the questionnaire was too lengthy. Of the 46 men who completed the preoperative questionnaire, 1 died postoperatively, 4 did not complete the 1-month questionnaire, and 1 man did not complete the 3-month questionnaire because of its length. There was no difference in scores in these 5 men compared with the 40 who completed the study. The final sample consisted of 40 pairs of men and women scheduled to undergo first-time CABS who were matched for BSA and were within 5 years of each other in age. Patients undergoing valvular surgery, combination bypass grafts and valve replacement, or re-do CABS were not included in the study. All subjects were able to read and write in English.
Procedures and instrumentation The instruments for the study were formulated into a questionnaire booklet that was initially administered in an interview format. For the 1-month and 3-month follow-ups, questionnaires were mailed to each subject. One week before the mailing of the questionnaire, the investigator called each subject to remind them of their participation in the study and the need to again complete the questionnaire. A self-addressed stamped envelope was included for subjects to return the completed questionnaire to the investigator. A follow-up reminder phone call was made if the questionnaire had not been returned within 10 days of the mailing and another questionnaire was sent if necessary. Demographic/medical information sheet. The demographic/medical information sheet was used to collect data on sociodemographics, medical history, current medications, and laboratory and cardiac catheterization results.
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Quality of life index. The Ferrans and Powers30 QLI measures satisfaction with various aspects of life as well as importance of each of these aspects to the individual. The cardiac version of the QLI was used in this study. Both the satisfaction and the importance section contain 32 items that ask respondents to rate on a 6-point Likert scale ranging from 1 (very dissatisfied/unimportant) to 6 (very satisfied/important) and form the following 4 subscales: health and functioning, socioeconomic, psychological/spiritual, and family. The range of scores for each subscale is 0 to 30. Scores are calculated by weighting each satisfaction response with its paired importance response, summing this response, and dividing by the number of items answered. Content validity was established using the Content Validity Index.33 Construct validity was established with factor analysis and correlations with the Campbell, Converse and Rodgers measure of life satisfaction (r ⫽ .77; P ⬍ .05).34 Cronbach alphas for the cardiac version of the QLI were reported as 0.86 in angioplasty patients,35 0.98 in coronary bypass patients,36 and 0.92 in patients undergoing cardiac rehabilitation.37 Social support: personal resource questionnaire. The PRQ38 measures the following domains of social support: provision for attachment/intimacy; social integration; opportunity for nurturant behavior; reassurance of worth as an individual and in role accomplishments; and availability of informational, emotional, and material help. The PRQ is designed to be self-administered and contains 2 sections. The first section, which provides descriptive information, contains questions regarding situations in which respondents might need assistance and the quality and availability of that assistance. Section 2 is composed of 25 items that ask respondents to rate on a 7-point Likert scale ranging from 7 (strongly agree) to 1 (strongly disagree) how they feel about relationships with others and their ability to count on others for help and support. The items are then totaled with high scores indicating higher levels of perceived social support. Reliability estimates have been obtained with 4 different data sets. In a sample of 120 men and women, Cronbach alpha was reported at 0.93.39 The range of alphas for the 3 other samples (149 adult white middle-class spouses of persons with multiple sclerosis, 77 low-income mothers, and 94 couples expecting their first child) ranged from 0.88 to 0.90. Weinert38 reported further alphas ranging from 0.88 to 0.93. Construct validity was supported by significant positive correlations with the support subscale of the Cost and Reciprocity Index (r ⫽ .52;
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P ⬍ .001) and the Inventory of Socially Supported Behaviors (r ⫽ .40; P ⬍ .001).38 This instrument has not been used in the cardiac population. Profile of mood states. The POMS40 measures the following perceived affective mood states: tension/ anxiety; depression/dejection; anger/hostility; vigor/ activity; fatigue/inertia; and confusion/bewilderment. Subjects are given a list of 65 feelings and asked to rate how intensely they have experienced these feelings over the past week on a 5-point Likert scale from 0 (not at all) to 4 (extremely). A score is obtained for each mood factor by summing the responses for the adjectives that define each mood factor. Two adjectives, relaxed in the tension subscale and efficient in the confusion subscale are scored negatively. A total score is obtained by summing the scores on each individual mood factor except for vigor, which is weighted negatively. High scores indicate high levels of negative mood states whereas low scores indicate a low degree of negative mood states. The total score for the POMS can range from 0 to 168. The range of scores for each mood state is as follows: anger (0-48), confusion (0-28), depression (0-60), tension (0-36), fatigue (028), and vigor (0-32). The instrument is designed to be self-administered with scores obtained by summing the responses for each adjective associated with a particular mood state. Reliability and validity data have been well supported in the literature.41,42 Symptom scale. The SS43 assesses the patients’ level of angina, SOB, and fatigue and the extent to which these symptoms interfere with overall functional ability. Subjects first state whether they were or were not experiencing each individual symptom by responding yes or no. If they were experiencing the particular symptom, a summated rating scale is used to rate the frequency of the symptom, severity of the symptom, how easily the symptom occurs, the extent to which the symptom interferes with physical activity, and the method used to treat each symptom. Subscale scores are obtained by summing the responses for each individual symptom and a total score is calculated by summing each subscale score. If subjects do not experience a particular symptom, a zero is assigned. Initial testing of the instrument was obtained on patients undergoing a treadmill test. Cronbach alpha for the entire scale was 0.91. Cronbach alphas were also adequate for each subscale. Concurrent validity was determined by correlation with metabolic equivalent level achieved on the treadmill (r ⫽ .66; P ⬍ .01). Overall health rating index. The OHRI43 consists of 5 questions designed to measure subjects’ perception of their overall health and activity. Re-
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sponses are measured on a summated rating scale and are totaled to obtain an overall score. Subjects are asked to rank how they perceive their level of activity, their level of health, and the extent to which symptoms interfere with their activity and health. Scores can range from 6 to 36 with high scores indicating a high level of perceived health and activity and low scores indicating a low perception of health and activity. Testing of the instrument revealed an alpha coefficient of 0.87. Concurrent validity was established by adequate correlation (r ⫽ .45; P ⬍ .001) with results on a treadmill exercise test. It was expected that subjects who rated their overall health and activity level high would also perform well on the treadmill exercise test. Specific activity scale. The SAS44 measures the level of physical activity by having respondents select from a list of specific activities those which they are able to perform without symptoms of chest pain, fatigue or SOB. The specific activities have corresponding metabolic equivalents and the respondents can be placed in a functional classification from I to IV based upon the associated MET guidelines assigned to each classification level (I ⫽ ⬎ 7 METs; II ⫽ 5-7 METs; III ⫽ 2-5 METS; and IV ⬍ 2 METs). Reliability of the SAS was determined by inter-rater reliability (2 ⫽ 6.85; P ⬍ .05) by having separate raters place respondents in the appropriate functional classification. Validity was determined by comparison of MET level achieved on the treadmill exercise test with MET level identified on the SAS (2 ⫽ 8.65; P ⫽ .013). Activities and their corresponding MET levels, which are more specific for women, were added to the original questionnaire for this study. Among these were gardening (5.0 METs), ironing (2.3 METs), moving furniture (5 METs), and putting away groceries (2.5 METs). In addition, MET levels assigned to each activity were summed and then averaged to obtain a specific mean MET level for each subject instead of using the classification scheme designed by the authors.
HYPOTHESIS The following research hypotheses were tested: 1. There will be differences between men and women matched on age within 5 years and BSA on the perceived physical domain of HQL at the preoperative, 1-month postoperative, and 3-month postoperative time periods. 2. There will be differences between men and women matched on age within 5 years and BSA on the perceived social domain of HQL at the
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preoperative, 1-month postoperative, and 3-month postoperative time periods. 3. There will be differences between men and women matched on age within 5 years and BSA on the perceived psychological domain of HQL at the preoperative, 1-month postoperative, and 3-month postoperative time periods.
DATA ANALYSIS Data were coded and analyzed using SPSS software version 8.0.45 Descriptive statistics were generated for sociodemographic information obtained as well as the QLI, the POMS, the PRQ, the OHRI and the SS for the sample as a whole and individually for both men and women. To determine presence of significant differences in the QLI, the POMS, the PRQ, the SS, and the OHRI between and within the groups of men and women preoperatively and at one month and three months postoperatively, a repeated measures ANOVA was performed. When significant F tests were found, post-hoc tests using the Bonferonni correction were used to determine where differences between genders occurred at the 3 respective time periods.46 An Analysis of Covariance (ANCOVA) was used if there were significant differences on the preoperative variables to control for those differences.
RESULTS Sample characteristics The sample consisted of 40 pairs of men and women matched on age within 5 years and BSA. All subjects were Caucasian. The mean age of women was 62.7 (SD ⫽ 12.1) years compared with 63.8 (SD ⫽ 10.8) years for men [t(79) ⫽ .37, P ⬎ .7]. The mean BSA was 1.8 (SD ⫽ 0.19) for women and 1.9 (SD ⫽ 0.19) for men [t(79)⫽ –1.82, P ⬎ .07]. The majority of both men (85%, n ⫽ 34) and women (75%, n ⫽ 30) were married. The mean years of school attended by women were 11.6 (SD ⫽ 2.2) compared with 12.2 (SD ⫽ 3.0) for men. The majority of women (80%, n ⫽ 32) and men (65%, n ⫽ 26) reported an annual income of less than $30,000. The majority of both women (95%, n ⫽ 38) and men (98%, n ⫽ 39) were either on Medicare, had private insurance or a combination of each.
Medical/physiologic data Medical data revealed a family history of heart disease was reported by 85% (n ⫽ 34) of women and 89% (n⫽ 35) of men. Thirty-eight percent of women (n ⫽ 15) and 20% of men (n ⫽ 8) were diabetic.
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Hypertension was present in 72% (n ⫽ 28) of the women and 58% (n ⫽ 23) of the men (2 ⫽ 1.07; df ⫽ 1; P ⬎ .28). Thirty-three percent (n ⫽ 12) of women had suffered a myocardial infarction before surgery compared with 58% (n ⫽ 23) of men (2 ⫽ 2.0; df ⫽ 1; P ⬎ .15). The majority of women (92%, n ⫽ 36) were postmenopausal, less than half of the women (36%, n ⫽ 14) reported ever using birth control pills, and less than half of the women (28%, n ⫽ 11) reported ever taking a hormone replacement. Women underwent a mean of 2.8 (SD ⫽ 0.8) bypass grafts compared with 3.2 (SD⫽ 0.9) for men. The number of bypass grafts was significantly lower in women [t(78) ⫽ –1.98; P ⫽ .05]. Analysis of laboratory data revealed no significant differences between women and men in serum glucose levels, blood urea nitrogen levels, serum creatinine levels, and triglyceride levels. Serum cholesterol levels were significantly higher in women (F ⫽ 211.3 ⫾ 44.6) than men (M ⫽ 178 ⫾ 33.4) preoperatively [t(78) ⫽ 3.09; P ⫽ .003].
Hypothesis 1: physical domain of HQL The first research hypothesis, regarding the perceived physical domain of HQL at the preoperative, 1-month postoperative, and 3-month postoperative time periods was accepted (Table I). Although improvements were seen for both women and men at both postoperative time periods, women did not respond as favorably on the outcomes measured when compared with men. Women reported significantly higher levels of total symptoms preoperatively compared with men. The total scores on the SS significantly decreased for both women and men at the 1-month and 3-month time periods compared with the preoperative time period. There were no differences in scores on the angina subscale between women and men and there were no differences in the numbers of women reporting experiencing angina at each time period compared with men (Table II).Women reported higher levels of SOB at all 3 times periods compared with men and significantly more women reported experiencing SOB at the preoperative and 1-month postoperative time periods compared with men (Table II). When controlling for the difference between women and men at the preoperative time period, women still reported significantly higher levels of SOB at 1 month postoperatively and 3 months postoperatively compared with men. There were no differences on the fatigue subscale of the SS on both the reported
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Table I Physical domain
Women (n ⴝ 40) Scale (Possible score)
Symptom Scale (0-81) Angina subscale (028) Shortness of breath subscale (028) Fatigue subscale (025) Health subscale QLI (0-30) MET average (0-8) Fatigue-POMS (0-28) Vigor -POMS (0-32) Overall Health Rating Index (6-36)
Preop
1 month
3 month
X (SD) 143.1 (24.6) 12. (11.4)
X (SD) 22.3 (11) 1.8 (4.5)
X (SD) 20.5 (15.8) 3.5 (6.4)
Within Women F statistic
42.1* 23.0*
Men (n ⴝ 40) Preop
1 month
3 month
X (SD) 34.4 (18.4) 11.2 (8.9)
X (SD) 14.9 (8.8) 1.7 (4.8)
X (SD) 15.8 (13.1) 3.1 (6.3)
Within Men
Between gender groups
F statistic
F statistic
61.3*
6.2*
36.2*
0.14
14 8.4 (10.7) 8.1)
7.2 (9.1)
13.8*
8.9 (9.7)
3 (6.0)
3.3 (6.6)
12.9*
16.9*
16.7 (6.0)
12 (4)
10.8 (6.5)
34.2*
14.7 (5.8)
10.2 (5.9)
11.5 (5.2)
24.0*
1.3
18.9 (5.1) 3 (0.63) 13.3 (7) 11.6 (5.8) 21 (6)
21.5 (3.9) 3.7 (0.46) 7.3 (5.6) 15.8 (6.9) 23.2 (4.8)
21.5 (5.2) 3.3 (.28) 7 (5.7) 15.9 (7.6) 22.9 (5.2)
7.2*
21.4 (4) 3.9 (0.41) 11.7 (4.9) 13.6 (6.7) 25.4 (4.4)
24.3 (2.6) 3.7 (.46) 6.3 (3.7) 20.2 (5.6) 27.7 (4.4)
25 (2.3) 3.8 (0.3) 5.5 (3.7) 21.3 (5.7) 27.74 (3.7)
49.9*
14.6*
2.8
7.4*
64.5*
2.5
41.5*
11.1*
6.8*
29.8*
10.5* 31.9* 12.8* 2.4
*P ⬍ .01 Note: An alpha of .01 was set for post hoc tests using the Bonferroni correction.
scores or in the numbers of women and men reporting feeling fatigued at each time period (Table 2). In addition, on the fatigue subscale off the POMS, there were no differences between women and men at any time period. The amount of perceived fatigue on the POMS subscale and the fatigue subscale of the SS did decrease significantly for both women and men at 1 and 3 months postoperatively compared with the preoperative time period. On the total QLI, women reported a statistically lower level of quality of life compared with men (F ⫽ 29.9, P ⬍ .001). Preoperatively, women reported a mean score of 20.9 (SD ⫽ 4.6) compared with 23.3 (SD ⫽ 3.2) for men. At 1 month postoperatively, women reported a mean score of 22.8 (SD ⫽ 4.0) compared with 24.6 (SD ⫽ 2.7) for men. Lastly, at
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the 3-month postoperative time period, women reported a mean score of 22.8 (SD ⫽ 4.6) compared with 25.7 (SD ⫽ 1.8) for men. Women reported a significantly lower quality of life on the health and functioning subscale of the QLI compared with men at each time period. When controlling for the differences preoperatively, women continued to report lower levels of HQL at both 1 month and 3 months postoperatively compared with men. For both women and men, scores on this subscale significantly improved at the postoperative time periods compared with the preoperative time period. In terms of activity, women reported lower mean MET levels compared with men preoperatively. When controlling for the differences preoperatively,
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Table II Numbers (percentages) of subjects reporting symptoms at each time period One month postoperatively
Preoperatively
Angina SOBa,b Fatigue
Three months postoperatively
Women n (%)
Men n (%)
Women n (%)
Men n (%)
Women n (%)
Men n (%)
25 (63%) 30 (73%) 39 (97%)
26 (65%) 20 (50%) 37 (92%)
6 (15%) 23 (58%) 39 (97%)
5 (12%) 8 (20%) 27 (67%)
11 (27%) 18 (45%) 34 (85%)
12 (30%) 12 (30%) 36 (90%)
a ⫽ Preoperatively X2(1) ⫽ 3.67; P ⫽ .05; b ⫽ One month postoperatively X2(1) ⫽ 4.99; P ⬍ .05.
women continued to report significantly lower mean MET levels at 3 months postoperatively compared with men. Whereas mean MET levels for men were unchanged across the time periods, mean MET levels at the 1-month time period were significantly higher than the preoperative time period in women. Though mean MET levels in women were also higher at the 3-month time period compared with the preoperative time period, they were not statistically significant. On the vigor subscale of the POMS, women reported significantly less vigor compared with men at both postoperative time periods. Vigor scores did significantly improve for both women and men at the 1 and 3-month postoperative time periods compared with the preoperative time period. Lastly, on rating their overall health, women reported significantly lower levels of perceived health at all 3 time periods compared with men. When controlling for the differences preoperatively, women continued to report lower levels of perceived health and activity at 1 and 3-months postoperatively compared with men. There were no changes in perceived level of health for women across the time periods, whereas men reported significantly increased levels of perceived health at the 1 and 3-month postoperative time periods compared with the preoperative time period.
Hypothesis 2: social domain of HQL The second research hypothesis, regarding the perceived social domain of HQL at the preoperative, 1-month postoperative, and 3-month postoperative time periods was also accepted (Table III).Women reported lower levels of social support on the socioeconomic subscale of the QLI at the 3-month
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postoperative time period compared with men. Scores for women remained unchanged on this subscale whereas men reported significantly higher quality of life on the socioeconomic subscale at the 3-month time period compared with the preoperative time period. There were no differences found on the family subscale of the QLI between women and men across the time periods. Women reported significantly higher family quality of life at the 1-month and three-month postoperative time periods compared with the preoperative time period. There was no change in scores for men across the time periods. There were no differences on the PRQ between women and men across the time periods. Scores for both women and men were unchanged across the 3 time periods.
Hypothesis 3: psychological domain of HQL The third research hypothesis, regarding the perceived psychological domain of HQL at the preoperative, 1-month postoperative, and three-month postoperative time periods was also accepted (Table IV).On the psychological subscale of the QLI, women reported significantly lower levels of psychological quality of life compared with men at the preoperative time periods. After controlling for the preoperative difference, there were no differences in scores at the 1-month time period, however, women scored significantly lower at the 3-month time period. Mean scores for both women and men were unchanged across the 3 time periods.
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Table III Social domain
Women (n ⴝ 40) Scale (Possible score)
Family subscale QLI (0-30) Personal Resource Questionnaire (25-245) Socio-economic subscale QLI (0-30)
Preop
1 month
3 month
X (SD) 22.8 (5.2) 140 (19.9)
X (SD) 25 (6.0) 142.2 (17.3)
X (SD) 25.9 (4.2) 141 (17.3)
23.2 (4.5)
23.8 (4.8)
23.5 (4.6)
Within Women F statistic
22.0* 0.042
0.27
Men (n ⴝ 40) Preop
1 month
3 month
X (SD) 25.8 (5.0) 145 (27.2)
X (SD) 26 (4.1) 141 (17.3)
X (SD) 26.8 (3.9) 139 (19.1)
24.5 (4.7)
24.9 (3.1)
26.2 (2.1)
Within Men
Between gender groups
F statistic
F statistic
2.0
3.5
1.1
0.04
5.1*
4.4*
*p ⬍ .01 Note: An alpha of .01 was set for post hoc tests using the Bonferroni correction.
On the POMS, women reported greater negative mood states at the 1-month and 3-month postoperative time periods compared with men. There were no differences at the preoperative time period. For both women and men, mean scores on the POMS significantly decreased at the 1-month and 3-month time periods compared with the preoperative time period. Examining the subscales of the POMS, there were no differences in anger, confusion and tension scores between women and men. Women reported no changes on the anger subscale at each time period whereas men reported significantly lower levels of anger at the 1-month and three-month postoperative time periods compared with the preoperative time period. Both women and men reported significantly less tension and confusion at the 1-month and 3-month postoperative time periods compared with the preoperative time period. On the depression subscale of the POMS, women reported significantly higher levels of depression at the preoperative time period. After controlling for this difference, there were no differences in reported levels of depression at the 1-month and 3-month time periods.
DISCUSSION The results of this study support results found in the literature that women do not have as favorable
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outcomes after CABS as men, particularly on the physical outcomes. The study adds to the current body of knowledge by controlling for age and body size and focusing on gender differences in quality of life before and after surgery. Both women and men did experience symptom relief after CABS. The majority of both women and men reported being free of angina after CABS, a finding that is supported with results found in published literature.9,15,19,47 Women continued to report feeling SOB in higher amounts compared with men postoperatively. Sjoland19 also reported significantly fewer women than men reported freedom from SOB 2 years after CABS. In this study, women received significantly lower numbers of bypass grafts compared with men, perhaps resulting in incomplete revascularization in women. The reason why women received fewer grafts is unknown. This may account for the continued SOB experienced by women. Women did report being able to perform activities at a higher mean MET levels at 1 and 3 months postoperatively indicating they were doing more activities after surgery compared with preoperatively whereas mean MET levels for men remained fairly constant. This increase in activity may also account for the continued feelings of SOB reported by women. Physical quality of life was poorer in women across the time periods as were overall perceptions of health. Physical quality of life included ratings of health on the
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Table IV Psychological domain
Scale (Possible score)
Psychological/ spiritual subscale QLI (0-30) Profile Of Mood States (0-168) Anger (0-48) Confusion (0-28) Depression (0-60) Tension (0-36)
Women (n ⴝ 40) Preop
1 month
3 month
X (SD) 122.1 (6)
X (SD) 23.4 (5.5)
X (SD) 22.9 (5.8)
48.5 (31.5)
19.4 (27.6)
20.6 (30.5)
6.5 (6.7) 8.3 (4.8) 15.4 (11.5) 15.7 (6.1)
4.9 (5.1) 6 (3.4) 8 (9.3) 9.9 (5.3)
4.6 (5.3) 6.3 (3.5) 8.4 (10) 9.1 (4.9)
Within Women F statistic
Men (n ⴝ 40) Preop
1 month
3 month
X (SD) 25.2 (4.5)
X (SD) 25.4 (3.2)
X (SD) 26.2 (2.8)
38.6*
40.4 (26.5)
9.6 (17.4)
3.3
8.1 (6.6) 9.2 (3.9) 10.9 (8.4) 14.5 (6.2)
3.1 (3.2) 5.7 (2.5) 4.6 (5.7) 9.8 (4.5)
1.9
9.1* 24.5* 50.6*
Within Men
Between gender groups
F statistic
F statistic
3.2
3.8*
8.9 (20.1)
49.3*
3.8*
4.1 (4.6) 5.8 (2.8) 5.6 (6.4) 9.1 (4.7)
10.0*
0.08
24.1*
0.02
13.4*
4.2*
40.3*
0.20
*P ⬍ .01 Note: An alpha of .01 was set for post hoc tests using the Bonferroni correction.
QLI, amount of SOB experienced, ability to perform activities of higher MET levels, levels of vigor and fatigue, and overall rating of health. In addition, women reported a lower quality of life on the total QLI. Since there were no differences found between women and men in terms of medical history, why women rated their physical and overall quality of life and overall health lower than men at the preoperative time period is unknown. Similarly, King47 found women reported lower quality of life scores compared with men preoperatively and at 1, 2 and 3 months postoperatively. Postoperatively, the higher level of symptoms, particularly SOB, may contribute to the lower ratings of HQL and overall health ratings seen in this study. Of significance are the higher levels of depression reported by women compared with men preoperatively. In this study, the level of depression reported by women is higher than scores reported on the depression subscale of the POMS in other studies. Czajkowski21 reported women, before surgery surgery,
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scored above a threshold score used to screen for clinical depression. The higher level of symptoms, lower levels of vigor, and lower perceived health ratings on the QLI could contribute to the higher depression ratings of women. Other authors51 also found women reported significantly more depressive symptoms compared with men and the depressive symptoms were correlated positively with pain. Because only 1 of the social support outcomes showed significance, no conclusions can be drawn about the possible impact of social support on the mood ratings of the women and men. In this study the majority of women and men were married, which may account for similar reportings of perceived social support. Overall, women in this study seemed to perceive that they experienced poorer outcomes after CABS compared with men preoperatively and at both the 1-month and three-month postoperative periods. The women reported lower levels of activity, vigor, and overall health rating and higher levels of SOB and depression.
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LIMITATIONS In this study it was difficult to obtain a male subject match for women on BSA. Several studies have reported women subjects had a smaller BSA than men.6 Loop11 reported a mean BSA for women of 1.66 compared with 1.92 for men. Similarly, Khan10 reported a mean BSA of 1.7 for women compared with 1.9 for men. A BSA of 1.8 would be equivalent to a person who is 5 feet 5 inches tall and 160 pounds. A person who is 5 feet 10 inches tall and 180 pounds would have a BSA of 2.0. The higher BSA in women in the current study was needed to find a match with available male subjects who generally have a higher BSA. To be able to find a match with a man, women with a BSA of 1.7 or above only were asked to participate in the present study resulting in a mean BSA of 1.8 for the female subjects. This is somewhat higher than reported in other studies and limits the generalizability of the results of the study to women with a BSA of 1.8 or above. The sample was homogeneous in regards to race. All subjects were Caucasian. Although efforts were made to include minorities in the sample, there were no minorities that fit the inclusion criteria available to participate in the study. Consequently, the results of the study are not generalizeable to all races. By study design, subjects were enrolled in the study as they were scheduled to undergo CABS so that the preoperative data could be obtained. Subjects who underwent emergent bypass surgery were eliminated from participation because the preoperative data would be difficult to obtain. Studies have shown differences between women and men in outcomes after CABS under emergent circumstances.50,51 The exclusion of subjects who underwent emergent CABS may have limited the differences found between women and men in the present study.
SUGGESTIONS FOR FURTHER RESEARCH Clearly, more prospective studies that examine differences between women and men are needed to validate our results. Studies need to include women of smaller size as well as men of larger size to determine if BSA is a factor in outcomes between women and men. Also, studies are needed which include subjects with more comorbid conditions undergoing CABS. Lastly, studies need to include minorities to understand outcomes after CABS and identify potential differences based not only on gender, but also
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on ethnicity. [The subjects in this study represent a relatively healthy population that may have accounted for the favorable outcomes seen postoperatively].
REFERENCES 1. American Heart Association. The 1999 Heart and stroke statistical update. Dallas: American Heart Association; 1998. 2. The Society of Thoracic Surgeons. Data analysis of the society of thoracic surgeons; 1991. 3. Bolooki H, Vargas A, Green R, Kaiser GA, Ghahramani A. Results of direct coronary artery surgery in women. J Thorac Cardiovasc Surg 1975;69(2):271-7. 4. Gardner TJ, Horneffer PJ, Gott VL, Watkins L Jr, Baumgartner WA, Borkon AM, Reitz BA. Coronary artery bypass grafting in women. A ten-year perspective. Ann Surg 1985;201(6):780-4. 5. Golding LR, Groves LK. Results of coronary artery surgery in women. Cleve Clin Q 1976;43(3):113-5. 6. Hannan EL, Bernard HR, Kilburn HC, O’Donnell JF. Gender differences in mortality rates for coronary artery bypass surgery. Am Heart J 1992;123(4 Pt 1):866-72. 7. Jamieson WR, Miyagishima RT. Aortocoronary bypass surgery in women. Can J Surg 1979;22(2):132-4. 8. Khan SS, Nessim S, Gray R, Czer LS, Chaux A, Matloff J. Increased mortality of women in coronary artery bypass surgery: evidence for referral bias. Ann Intern Med 1990; 112(8):561-7. 9. Loop FD, Golding LR, MacMillan JP, Cosgrove DM, Lytle W, Sheldon WC. Coronary artery surgery in women compared with men: analysis of risks and long-term results. J Am Coll Cardiol 1983;1:383-90. 10. Richardson JV, Cyrus RJ. Reduced efficacy of coronary artery bypass grafting in women. Ann Thorac Surg 1986;42(6 Suppl): S16-21. 11. Edwards FH, Carey JS, Grover FL, Bero JW, Hartz RS. Impact of gender on coronary bypass operative mortality. Ann Thorac Surg 1998;66(1):125-31. 12. Douglas JS Jr, King SB 3rd, Jones EL, Craver JM, Bradford JM, Hatcher CR Jr. Reduced efficacy of coronary bypass surgery in women. Circulation 1981;64(2 Pt 2):II11-6. 13. Eaker ED, Kronmal R, Kennedy JW, Davis K. Comparison of the long-term, postsurgical survival of women and men in the Coronary Artery Surgery Study (CASS). Am Heart J 1989; 117(1):71-81. 14. Killen DA, Reed WA, Arnold M, McCallister BD, Bell HH. Coronary artery bypass in women: long-term survival. Ann Thorac Surg 1982;34(5):559-63. 15. Golino A, Panza A, Jannelli G, Vigorito C, Giordano A, Persico S, et al. Myocardial revascularization in women. Tex Heart Inst J 1991;18:194-8. 16. Jeffery DL, Vijayanagar RR, Bognolo DA, Eckstein PF. Results of coronary bypass surgery in elderly women. Ann Thorac Surg 1986;42(5):550-3. 17. Tyras DH, Barner HB, Kaiser GC, Codd JE, Laks H, Willman VL. Myocardial revascularization in women. Ann Thorac Surg 1978;25(5):449-53. 18. Rahimtoola SH, Bennett AJ, Grunkemeier GL, Block P, Starr A. Survival at 15 to 18 years after coronary bypass surgery for angina in women. Circulation 1993;88(5 Pt 2):II71-8. 19. Sjoland H, Caidahl K, Karlson BW, Karlsson T, Herlitz J. Limitation of physical activity, dyspnea and chest pain before and two years after coronary artery bypass grafting in relation to sex. Int J Cardiol 1997;61(2):123-33. 20. Sjoland H, Wiklund I, Caidahl K, Haglid M, Westberg S, Herlitz J. Improvement in quality of life and exercise capacity after coronary bypass surgery. Arch Intern Med 1996;156(3): 265-71.
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