Evaluation of a nurse-delivered smoking cessation intervention for hospitalized patients with cardiac disease

Evaluation of a nurse-delivered smoking cessation intervention for hospitalized patients with cardiac disease Joy L. Johnson, PhD, RN,a Bernice Budz, MSN, RN,b Martha Mackay, MSN, RN,b and Clara Miller, BScN, RN,a, Vancouver, British Columbia OBJECTIVE: To determine the effect of a nurse-delivered smoking cessation intervention for hospitalized smokers on smoking cessation rates and smoking cessation self-efficacy at 6 months after enrollment. DESIGN: A quasi-experimental design was used; specifically, a nonequivalent control group design was implemented. SETTING: A 450-bed major teaching and research tertiary care hospital, serving patients from across the province of British Columbia, Canada. SUBJECTS: Smokers with a cardiac diagnosis (n = 102) who were admitted to 1 of 2 inpatient cardiac units for medical or surgical treatment. OUTCOME MEASURES: Self-reported smoking status and self-reported smoking cessation self-efficacy. INTERVENTION: Two structured, in-hospital contacts, followed by 3 months of telephone support. The interventions focused on problem-solving and reinforcing the patient’s self-efficacy. RESULTS: Of the patients enrolled, 86 completed 6-month follow-up questionnaires. When subjects who were lost to follow-up were assumed to be smokers, 46% of the intervention group, compared with 31% of the control group, were nonsmokers. When key variables were controlled, we found that those subjects in the control group were 3 times more likely to relapse and begin smoking than those who received the intervention. There were no significant differences in follow-up smoking cessation self-efficacy scores in the treatment and control groups. When background variables were controlled, self-efficacy related to positive/social situations and habit/addictive situations were noted to be significantly higher in the intervention group. CONCLUSION: The findings of this research are encouraging; they suggest that a nurse-delivered smoking cessation intervention improved the smoking cessation rate in patients with cardiac disease. (Heart Lung® 1999;28:55-64)

T

he negative health consequences of smoking are increasingly recognized and understood. There is a well-documented and strong asso-

From the aSchool of Nursing, University of British Columbia, and bSt. Paul’s Hospital, Vancouver. This research was supported by grants from the British Columbia Health Research Foundation, the Woodward Foundation, and The British Columbia Medical Services Foundation. Reprint requests: Dr. Joy Johnson, School of Nursing, University of British Columbia, T201-2211 Wesbrook Mall, Vancouver, BC V6T 2B5. Copyright © 1999 by Mosby, Inc. 0147-9563/99/$8.00 + 0 2/1/93947

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ciation between smoking and morbidity and mortality rates from respiratory, cardiovascular, and neoplastic conditions.1,2 Cessation of smoking is an important positive step that people can take to improve their health. Scientific evidence overwhelmingly supports the claim that smoking cessation can lower morbidity and mortality rates.3,4 Currently in Canada, 28% of the population are reported to smoke cigarettes every day.5 It has been suggested that the hospital setting represents a valuable opportunity for the initiation of cessation interventions for several reasons. First, serious illness may motivate patients to quit,

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because the threats of cigarette smoking become personalized.6-9 Also, because of hospitals’ smokefree policies, patients are often nicotine-free for a period of days and may then be willing to maintain this state over a long period of time. Finally, periods of hospitalization have been described as “teachable moments” in which patients are particularly amenable to smoking cessation interventions.9 Unfortunately, most health professionals do not take advantage of this opportunity, perhaps because they lack knowledge of interventions that can be used to help patients change their smoking behaviors.10 Most often, patients are told by health professionals to quit smoking, but are not offered the support and information necessary for success.

Review of the Literature Smoking cessation interventions have been available since before 1900, and many different methods have been advocated. These have included drug treatments, hypnosis, acupuncture, professional counseling, aversive conditioning, and a wide variety of behavioral self-management strategies. Numerous studies have focused on the attributes of successful smoking cessation interventions. Despite the variety of cessation methods available and the numerous studies conducted, findings related to the effectiveness of interventions are largely unimpressive. One group of researchers concluded that the format of a smoking cessation program does not influence cessation rates.12 Indeed, based on an evaluation of smoking cessation programs during the period of 1978 through 1985, Schwartz8 argued that cessation rates reported by formalized programs are probably more influenced by smoker selection than by the treatment methods themselves. Although no particular method has been demonstrated to be the panacea for smoking cessation, there appear to be some approaches that more effectively facilitate cessation. For example, it has been found that health education methods are more effective in changing smoking behavior when tailored to the individual smoker.13 Similarly, the evidence suggests that the most effective smoking cessation programs involve a variety of methods and techniques, are highly structured in their approach, focus on developing cessation skills, and emphasize maintenance of cessation.14 The Agency for Health Care Policy and Research (AHCPR) has developed guidelines on smoking cessation treatments that are based on an expert panel’s exhaustive literature review.15 The guidelines offer several key practice recommendations

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for practitioners and smoking cessation specialists. First, all patients who smoke should be offered smoking cessation treatment. Second, a doseresponse relationship between intervention intensity and smoking cessation success appears to exist. Third, counseling content should include problem solving, skills training, and social support. Fourth, nicotine replacement can play a valuable role in helping clients to quit smoking and should be offered to clients contemplating cessation, except in the presence of serious medical precautions. Several studies have focused on the factors that facilitate or hinder a person in the smoking cessation process. One such factor is the degree to which an individual is addicted to nicotine. Studies have revealed that individuals with high levels of addiction have more difficulty with the cessation process.16-18 A second factor is self-efficacy. Strecher et al19 identified 13 studies in which the self-efficacy construct was examined in the area of smoking and smoking cessation. Ratings of self-efficacy were found to discriminate active quitters from continued smokers, joiners of smoking cessation programs from non-joiners, and successful quitters from unsuccessful quitters. Probably most encouraging is the evidence Strecher et al19 provided that demonstrated that experimental manipulations of self-efficacy can enhance self-efficacy, and that this enhancement was related to subsequent smoking cessation. In the 10 years since the Strecher et al19 review, evidence has continued to accumulate that demonstrates that interventions aimed at enhancing self-efficacy produce significant smoking cessation results in a variety of populations.20-22 Researchers have found that encouragement from significant others is associated with successful smoking cessation.23-25 In a review of the influence of social support on quitting smoking, Colletti and Brownell26 concluded that quitting smoking and remaining abstinent are related to family and peer pressures. The effectiveness of smoking cessation interventions that begin during hospitalization is beginning to receive research attention. The handful of reported studies has suggested that hospital-initiated programs may provide an effective mechanism for helping individuals quit smoking. A randomized trial of a nurse-managed intervention for smoking cessation in patients diagnosed with myocardial infarction (MI) yielded a cessation rate of 71% in the intervention group compared with 45% in the usual care group.27 Both of these rates are higher than the unaided cessation rate of 7.33%

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reported in the general population.28 In a subsequent study of hospitalized smokers with varied medical and surgical diagnoses, the 12-month cessation rates were 31% for the treatment group and 21% for the usual care group.29 In contrast, a nonexperimental study that focused on evaluating whether nursing interventions could help patients quit smoking revealed that only 17% of the patients who were observed for 1 year had successfully given up smoking.30 It also has been reported that nurse-delivered interventions are more effective than self-help material.31 In addition, the evidence suggests that nurse-delivered interventions are particularly effective among smokers with an identified smoking-related medical diagnosis.9 Some research suggests that contextual barriers external to the patient, such as nurses’ role perceptions and status, hospital policies, and hospital routines, can influence the effectiveness of intervention programs.10 Feasibility of a nurse-delivered smoking cessation intervention within the Canadian context has not been tested. In light of this need, a study was conducted to evaluate the effectiveness of a nurse-delivered smoking cessation intervention for hospitalized patients with cardiac disease. The study was designed to test the following hypotheses: H1—Hospitalized smokers who receive a nurse-delivered smoking cessation intervention will, at 6 months after discharge, have higher smoking cessation rates than those who did not receive the intervention; H2—Hospitalized smokers who receive a nurse-delivered smoking cessation intervention will, at 6 months after discharge, have better smoking cessation self-efficacy than those who do not receive the intervention. A secondary purpose of this study was to determine whether physical, psychologic, and social factors influenced the efficacy of the intervention.

METHODS Design. To determine the effectiveness of the intervention, a quasi-experimental design was used. Recruitment procedures were initiated after the third postoperative day for surgical patients and once medical patients were deemed to be stable. Those subjects admitted to the intervention unit who gave informed consent received the nurse-delivered smoking-cessation intervention. Although an experimental design offers more control, it was believed that hospitalized patients with cardiac disease might interact with one another and share information. It was argued that such mingling might contaminate the control group and

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could pose a serious threat to the internal validity of the study. Accordingly, we used a non-equivalent control group design. The subjects admitted to the control unit received usual care. Usual care consisted of occasional advice to quit smoking from physicians and nurses; no organized smoking cessation counseling was available to patients in the control group. All subjects were mailed a follow-up questionnaire 6 months after the initial contact in the hospital. Setting. The study was conducted at a 450-bed major teaching and research tertiary care hospital, serving patients from across the province of British Columbia, Canada. All areas of the hospital are designated as nonsmoking. The recruitment sites for the study were the 2 cardiac units. The units contain similar types of patients, and a single pool of cardiologists and cardiac surgeons admits patients to both units. Before commencement of the study, the clinical nurse specialists associated with the 2 units noted no differences in relation to the information given to patients about cardiac risk reduction. In addition, no changes in cardiac riskreduction education, including smoking cessation, were noted on the control unit during the course of the study. Patients belonged to a single pool and were admitted to either unit, depending on bed availability. One of the units was randomly designated as the treatment unit; the other unit was designated as the control unit. Each unit had a separate professional nursing staff and was independently managed. Sample. Patients with cardiac disease who were self-reported smokers, were in the contemplation stage of smoking cessation, were admitted to 1 of the 2 hospital cardiac units with an projected length of stay longer than 3 days, and were physiologically stable were recruited to the study. Other criteria for entrance into the study were (1) 19 years of age or older, (2) self-reported use of tobacco for at least the past year, (3) no overt signs of mental confusion, (4) possessed either or both a medical or surgical cardiac diagnosis, (5) ability to understand and to communicate in English, and (6) access to a telephone for follow-up intervention. Intervention. The intervention was based on 5 principles: (1) smoking cessation is a process, (2) individuals choose to quit smoking; they cannot be forced, (3) smoking cessation interventions need to be individualized and stage-matched, (4) people perceive that they have the skills and ability to quit smoking if they are to be successful (smoking cessation self-efficacy), and (5) cessation efforts must be reinforced with long-term follow-up. In addition,

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the initial intervention was designed to be brief so that, if implemented as hospital protocol, a nurse working on a unit could feasibly provide the intervention. The intervention consisted of 2 contacts by the intervention nurse while the patient was in the hospital, followed by 6 telephone contacts during the first 3 months after discharge. In the initial encounter, subjects were instructed to watch the first 19-minute portion of a video entitled “The Smoke-Free Habit”32 in which the effects of smoking, the importance of smoking cessation, the smoking cessation process, and smoking triggers were reviewed. The video prompted subjects to answer key questions about their own smoking habit, and they were provided a worksheet on which to record their answers. After the video, the intervention nurse discussed patients’ answers with them to help them understand their particular smoking habit. The nurse answered questions about smoking, and encouraged subjects to set a firm quit date, preferably that same day. At the close of the first intervention, the patient was given the booklet “A Lifetime of Freedom From Smoking”33 and was asked to review it. The focus of the second in-hospital contact was on developing and reinforcing skills that could assist subjects in quitting smoking. The nurse began the second session by reviewing the material covered the previous day. Subjects watched the second 9-minute portion of the video in which approaches to smoking cessation were reviewed. The intervention nurse then helped subjects to develop a smoking cessation plan, including strategies for dealing with perceived triggers to cigarette smoking. Where appropriate, the nurse encouraged subjects to practice or rehearse responses. After being discharged, patients received telephone follow-up by the nurse who delivered the in-hospital portion of the intervention. Telephone calls were made weekly for the first month and then monthly for the following 2 months. A total of 6 telephone contacts were made. The purpose of the telephone contacts was to encourage and reinforce cessation efforts. These calls were driven by the needs and concerns voiced by the subjects and ranged in duration from 5 minutes to 1 hour. Throughout the intervention, several strategies were used to enhance the patient’s sense of selfefficacy. The nurse provided positive reinforcement for all efforts made to quit smoking; in addition, where appropriate, statements were used by the nurse to reinforce the patient’s belief that the strategies that he or she was using were effective

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and that persistent use of these strategies would achieve positive results (thus enhancing efficacy expectations). The nurse focused on helping the patient develop and, where appropriate, practice the skills necessary for smoking cessation. Similarly, the nurse encouraged the patient to identify and use strategies that had been successful for them in the past. To enhance outcome expectations, the nurse encouraged the patients to “break down” the smoking cessation process into steps that they believed were manageable. These strategies are consistent with those listed in the Nursing Intervention Classification34 and are considered effective ways to enhance self-efficacy. Measures. At baseline, and at 6 months after initial contact, all subjects completed a questionnaire. The questionnaire contained items and scales that measured smoking status, smoking cessation self-efficacy, physical dependence on tobacco, perceived support for smoking cessation, perceived stress, and demographic variables. Items that measured smoking status, number of cigarettes smoked per day, number of years of smoking, number of prior attempts to quit, readiness to quit smoking, and longest previous abstention period were derived from the Smoking Follow-up Questionnaire.35 These items have been used in numerous studies on tobacco use and appear to be comprehensible. Although the measurement of smoking status by biochemical means such as saliva cotinine levels is recognized by many as the gold standard, a biochemical measure was not used in this study, primarily because of the associated expense. However, self-report of smoking status was used in this study, because this method of reporting has been found to provide reasonably accurate accounts of smoking status.36 Smoking cessation self-efficacy was measured using the Smoking Abstinence Self-Efficacy Scale (SASE),37,38 an instrument designed to assess smokers’ level of confidence that they will not smoke in 20 challenging situations, including positive/social situations, negative/affective situations, and habit/addictive situations. Level of confidence was indicated on a 5-point Likert scale from 1— “Not at all confident” to 5—“Extremely confident.” This instrument has demonstrated acceptable construct and predictive validity and acceptable internal consistency (Cronbach’s alpha ranges from 0.88 to 0.92).37-39 The data obtained in this study were subjected to factor analysis with maximum likelihood extraction and varimax rotation, which confirmed the presence of 3 factors. The alpha coefficients were 0.82 for the positive/social subscale,

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Table I Comparison of groups by demographic characteristics Group Variable

Age Sex (%) Male Female Marital status (%) Married/Common-law Not married Education (%) Attended high school Completed high school University/college Attended Completed Income (%) < $39 999 > $40 000 Perceived Stress Scale Cardiac surgery Yes No

Statistic

Control (n = 52)

Experimental (n = 50)

t Test

Chi-square

55.4 (12.97)

54.8 (12.56)

–0.252

—

78.8 21.2

72.0 28.0

—

61.5 38.5

66.0 34.0

—

45.1 15.7

36.7 16.3

31.4 7.8

32.7 14.3

— —

1.39

72.7 27.3 2.79 (0.650)

50.0 50.0 2.76 (0.667)

— — 0.984

4.89* —

63.5 36.5

44.0 56.0

—

0.30 0.22

3.89*

*P < 0.05.

0.92 for the negative/affective subscale, and 0.85 for the habit/addictive subscale. Physical dependency on tobacco was measured using the Tolerance Questionnaire (TQ).40 The TQ is an 8-item scale designed to measure physical dependence on nicotine. The questionnaire combined responses about the smoking habit (number of cigarettes smoked, minutes to first morning cigarette, smoking while ill, and so on) to create a measure of addiction. Possible scores range from 0 to 11, with higher scores being indicative of higher levels of addiction. The TQ has successfully been used to discriminate levels of addiction, withdrawal responses, heart rate, and past smoking behavior. A revised version of this scale called the Fagerstrom Test for Nicotine Dependence (FTND) was developed by Payne et al.41 Using a sample of 110, these authors noted “modest” improvements in the reliability of FTND, but recommended further psychometric testing. Subsequent studies have revealed that the TQ is as valid a predictor of smoking cessation as the FTND.42,43 Given the evolving evidence related to the reliability and validity of

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the FTND, the decision was made to use the original scale. Two items were used to measure anticipated social support for smoking cessation. Each patient was asked how much encouragement from other household members he or she would expect if he or she were to quit smoking. This item was used by Strecher23 in a smoking cessation study. He argued that the concept of encouragement traverses key elements of social support. A second item was used to measure exposure to other smokers, and the degree to which the individual is in contact with others who smoke. Because it has been argued that stress can interfere with the ability to make and maintain a behavior change,44 perceived stress was measured using the Perceived Stress Scale (PSS).45 The PSS was designed to describe how unpredictable, uncontrollable, and overloaded respondents find their lives. It is considered a global measure of how much perceived stress subjects have experienced in the past month. The scale contains 14 items and has been judged to be a useful measure of per-

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Table II Baseline smoking characteristics by group Group Variable

Years of smoking Baseline self-efficacy scores (SASE) Positive/Social Negative/Affective Habit/Addictive Nicotine dependence (TQ scores) Previous quit attempts in past year (%) Never ≥ 1 Time Social support (1 = no support, 4 = a great deal of support) From family From friends No. of social contacts who smoke (%) Some/none Most/all

Control

35.3 2.87 2.76 3.29 6.1 36.5 63.5 3.44 3.06 57.7 42.3

Statistic

Experimental

35.1 3.32 2.85 3.32 6.8 46.9 53.1 3.46 3.04 64.0 36.0

t Test

Chi-square

0.08

—

4.59* 0.13 0.12 –1.76

— — — —

— —

— 1.12

–0.09 –1.43

— —

0.46 —

— —

*P < 0.05.

ceived stress for situations requiring a short scale. The possible range of scores is between 1 and 4, with 4 being indicative of severe stress. Coefficient alpha reliability has been reported to range from 0.84 to 0.86 in various samples. Concurrent validity was established by significant correlations with lifeevents scores, and predictive validity was evidenced by low, significant correlations to health care utilization and smoking reduction maintenance.41 Sociodemographic information was collected and the subject’s admitting diagnosis was recorded. The demographic items used have been adapted from well-established surveys such as Canada’s Health Promotion Survey and have undergone rigorous pretesting.

CHARACTERISTICS OF THE SAMPLE During 1 year of recruitment from July 1995 to June 1996, 2042 patients were screened, and 303 (15%) patients were identified as smokers. Of these patients, 129 (43%) were deemed eligible. Primary reasons for ineligibility included a lack of language skills, disorientation, or lack of desire to quit smoking within the next 6 months. Of those eligible, 79% agreed to participate. In total, 102 patients met the inclusion criteria and agreed to participate in the

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study (52 subjects in the control group and 50 subjects in the treatment group). The average age of the subjects was 54.9 years (SD = 12.59). The majority of subjects were married men with less than a high school education. The average family income of the subjects was relatively low, with more than half reporting that their annual income was less than $40 000 per annum. Forty-seven percent of the sample was admitted for cardiac surgery, whereas the remainder were admitted for nonsurgical reasons such as MI. Perceived Stress Scale scores were found to be relatively high (M = 2.7; SD = 0.65). The experimental and control group were found to be equivalent with respect to most demographic characteristics, with the exception of higher income and more surgical intervention in the experimental group (Table I). The subjects enrolled in the study reported that they had smoked from 6 to 62 years, with the average number of years of smoking being 35.2 years (SD = 13.20). Addiction to nicotine scores (TQ scores) ranged from 1.0 to 11.0, with a mean of 6.5 (SD = 2.16). The baseline SASE score’s mean subscale scores were 3.09 (SD = 1.07) for the positive/social subscale, 3.30 (SD = 1.07) for the habit/addictive subscale, and 2.8 (SD = 1.25) for the negative/affective subscale. In relation to experience with smoking cessation, 41.6% reported that

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Table III ANCOVA of 6-month smoking abstinence self-efficacy scores Source of variance

SS

df

MS

F

Positive/Social self-efficacy

Baseline positive/ Social self-efficacy Group assignment Error

18.66

1 18.66 11.48*

Nicotine dependence (TQ score) Most/All Some/None

1

2.47

1.52

Group assignment

133.27 82

1.63

7.67

Control Intervention

2.47

Odds ratio

1.37*

95% CI

1.07-1.74

Negative/Affect self-efficacy

22.68

0.29

1 22.68 10.19*

1

0.29

182.54 82

2.22

0.13

SS, Sums of squares; MS, mean square. *P < 0.05.

they had not attempted to quit smoking in the past year. Most subjects anticipated that they would receive a great deal of support from family (M = 3.45; SD = 0.98) and friends (M = 3.42; SD = 1.01) in their cessation attempts. When asked to indicate how many of the people they spent free time with were smokers, most (61%) indicated that none or some of their social contacts were smokers, and the remainder indicated that most or all were smokers. In relation to group differences, we found that the SASE scores were not equivalent at baseline, with the treatment group having significantly higher positive/social self-efficacy scores at baseline. There were no other group differences in smoking histories noted (Table II).

RESULTS All subjects were contacted at 6 months after discharge, at which time self-reported smoking

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4.99* 1.00

1.67-14.81

3.18* 1.00

1.15-8.77

*P < 0.05.

Baseline Habit/ 23.08 1 23.08 14.22* Addictive self-efficacy Group 0.68 1 0.68 0.42 assignment Error 133.06 82 1.62

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Variables

No. of social contacts who smoke

Habit/Addictive self-efficacy

Baseline Negative/ Affect selfefficacy Group assignment Error

Table IV Mixed-effects logistic regression model of smoking resumption 6 months after enrollment

behavior data were collected. Of the initial 102 subjects enrolled, 5 were deceased at 6 months, and 11 were lost to follow-up, leaving a total of 86 subjects: 42 in the intervention group and 44 in the control group. The remaining findings focus on these 86 subjects. Hypothesis1. When subjects who were lost to follow-up were coded as smokers, 46.0% of the intervention group were found to be nonsmokers compared with 30.8% of the control group. Although we believe this difference to be of clinical significance, the difference was not statistically significant (c2[1,N = 102] = 2.94; P = 0.23). Hypothesis2. We had hypothesized that the intervention would significantly increase the subjects’ smoking cessation self-efficacy. When we compared the intervention and control groups’ SASE scores at 6 months, controlling for baseline scores, we found there was no difference between treatment and control group SASE scores (Table III). Multivariate analysis. To control for possible covariates that may have confounded the study results, logistic regression was undertaken in which those who reported quitting smoking were contrasted with those who resumed smoking. Smoking history covariates, and those background covariates that were found to differ between the 2 groups at baseline, were controlled (income and whether the subject was a surgical patient). The covariates were entered en bloc, and group assignment (either control or experimental) was then entered in a second block. Those variables that were not statistically significant were removed from the model to minimize the effect of missing data. Next, we tested for interactions between the significant covariates and found none, and so the interaction

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Table V Stepwise multiple regression analysis of smoking abstinence self-efficacy (n = 86) Variable

B

b

R

R2

F Value

0.44 0.53 0.58

0.20 0.28 0.33

17.63* 13.82* 11.71*

0.45 0.58 0.62

0.20 0.34 0.39

18.41* 18.53* 14.95*

0.37 0.47 0.53

0.13 0.20 0.25

11.54* 10.26* 9.35*

Dependent variable = predictors of positive/social self-efficacy

Baseline positive/social self-efficacy Nicotine dependence (TQ score) Assignment to the treatment group Constant

0.42 –0.23 0.67 3.00

0.34 –0.37 0.25

Dependent variable = predictors of habit/addictive self-efficacy

Nicotine dependence (TQ score) Baseline habit/addictive self-efficacy Assignment to the treatment group Constant

–0.28 0.44 0.61 3.18

–0.45 0.38 0.27

Dependent variable = predictors of negative/affective self-efficacy

Baseline negative/affective self-efficacy Nicotine dependence (TQ score) Years of smoking

0.37 –0.18 0.01

terms were removed from the model. The final model found in Table IV demonstrates that, when the significant covariates were controlled or held constant, those in the control group were 3 times as likely to resume smoking as those in the intervention group. Not surprisingly, the other significant predictors of smoking were nicotine addiction and spending time with people who smoke. To determine whether the self-efficacy subscale scores were affected by group differences, we performed step-wise multiple regression analyses in which we controlled for the effects covariates described above and baseline self-efficacy scores. These analyses revealed that, with background variables controlled, group assignment (being in the treatment group) was found to positively affect habit/addictive and positive/social SASE scores (Table V). The predictors of positive/social and habit/addictive self-efficacy scores at 6 months included baseline self-efficacy scores, TQ scores, and being assigned to the treatment group. Those with higher baseline self-efficacy scores, lower TQ scores, and who were assigned to a treatment group were more likely to have higher self-efficacy scores at 6 months. In the case of negative/affective self-efficacy scores, the significant predictors included baseline self-efficacy scores, TQ scores, and the number of years a person had smoked. Although the effect was small, this third regression model suggests that those who had smoked for more years were more likely to have higher nega-

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0.33 –0.30 0.25

tive/affective self-efficacy scores. The 3 regression models accounted for between 25% and 39% of the variance in self-efficacy subscale scores.

DISCUSSION The findings of the study should be viewed with caution in that smoking status was measured using self-report and was not biochemically validated. Some underreporting of smoking may have occurred. In particular, smokers with smoking-related diagnoses may feel compelled to report to heath care practitioners that they are not smoking.46 Another limitation of the study is a 16% attrition. To ensure that those subjects who were deceased or lost to follow-up did not bias results, we undertook analyses focusing on smoking cessation rates again—with all subjects lost to follow-up recoded as smokers. Finally, it must be acknowledged that the nonsignificant findings may have been due to Type II error. Despite these limitations, the study results contribute to an emerging body of literature related to smoking interventions for patients with cardiac disease. Although the 2 hypotheses were not supported, the findings provide indirect evidence that a nurse-delivered smoking cessation intervention can lead to positive outcomes. The cessation rate at 6 months was 46% in the treatment group and 31% in the control group. Although these differences were not statistically significant, they are promising in that they reveal a

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substantial decrease in self-reported smoking among those receiving the intervention. When group differences were controlled, the contribution of the intervention becomes more apparent, with those in the control group having 3 times the chance of resuming smoking than those in the intervention group. It is interesting to compare the cessation rates found in this study with those reported in comparable studies. Working with patients with MI, Taylor et al27 found that a nurse-managed cessation intervention yielded cessation rates of 61% in the intervention group and 32% the control group at 12 months after MI. In a second study that focused on hospitalized patients, Taylor et al29 reported that 31% of the intervention group and 21% of the control group had quit smoking at 12 months after hospitalization. Although their sample of cardiovascular subjects was small (n = 22), Wewers et al9 reported that a nurse-delivered intervention yielded 5-week cessation rates of 40% of those in the intervention group compared with 8% of those in the control group. Finally, Rice et al30 reported a counterintuitive 12-month cessation rate of 14% among subjects who had received an individualized smoking cessation intervention compared with a 30% cessation rate of control subjects. It is acknowledged that comparisons with other studies should be made with caution because, unlike the studies reported above, smoking status in the present study was not biochemically validated. As the evidence from these trials of smoking cessation interventions accumulates, we can begin to uncover answers to questions concerning their effectiveness and the elements that might improve their efficacy. For example, unlike the other studies, the intervention tested by Rice et al30 did not involve an intensive follow-up of subjects. This provides further evidence that follow-up may be an important element of smoking cessation. The intervention did appear to have some effect on self-efficacy scores, specifically efficacy related to positive/social and habit/addictive situations. It is interesting to note that, despite the high levels of relapse, the subjects tended to report a great deal of confidence related to smoking cessation at baseline. Similarly, Taylor et al27 found that, at baseline, subjects reported an overall confidence of 80% that they would be able to successfully quit smoking. Because of these high confidence scores at baseline, changes in self-efficacy may have been undetectable. Alternatively, it may be that the intervention works through a mechanism other than self-efficacy. For example, 1 alternative explanation is that the nurse

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provided meaningful social support that helped to bolster the subjects’ resolve to quit smoking. This study adds to the body of literature that points to the potential effectiveness of nursedelivered smoking cessation interventions. It is acknowledged that the costs associated with the intervention tested in this study may prove prohibitive and that future research attention must be paid to determining the key elements that can make a difference. Future research that uses a larger sample is needed to build on this work and to examine how the intervention can be successfully disseminated in nursing practice. In addition, there is a need to move from efficacy trials to effectiveness trials. Evidence is beginning to accumulate that nurses can make a difference. There are many barriers that must be overcome, however, before they take up the counseling of patients who smoke.47 The next questions that must be answered are how these barriers can be overcome and whether nurses can incorporate such interventions into their practice.

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