- Email: [email protected]
Smoking and health outcomes after percutaneous coronary intervention
Outcomes, Health Policy, and Managed Care
Smoking and health outcomes after percutaneous coronary intervention C. Keith Haddock, PhD, Walker S. C. Poston, PhD, Jennifer E. Taylor, MA, Mark Conard, MA, and John Spertus, MD, MPH, FACC Kansas City, Mo
Background This study was designed to describe the impact of smoking on health status and mortality after percutaneous coronary intervention (PCI).
Methods A cohort of 271 consecutive PCI patients at the Mid-America Heart Institute of St Luke’s Hospital in Kansas City, Mo, were observed in a prospective, observational study. Surveys that included health status assessments were administered at baseline and at 6 and 12 months after intervention. Primary outcome was health status as measured by the Short Form-12 (SF-12) and the Seattle Angina Questionnaire (SAQ).
Results Risk-adjusted statistical models demonstrated that, across a number of health-related quality of life domains, patients who were current smokers had poorer health status outcomes than other patients after revascularization. For instance, patients who had never smoked (P ⬍ .001) and patients who were former smokers (P ⬍ .001) scored significantly higher than patients who were current smokers on the physical component score of the SF-12, which indicated a better sense of overall physical function. Similarly, patients who had never smoked and patients who were former smokers reported significantly fewer physical limitations, less angina, and a higher quality of life on the SAQ than patients who were current smokers. Smoking status was unrelated to mortality rate in the 12 months after revascularization. Conclusions Smoking substantially limits the potential health status benefits of PCI. (Am Heart J 2003;145:652-7.) Percutaneous coronary interventions (PCI) are a highly effective therapy in the treatment of coronary artery disease.1 Since the introduction of PCI in the late 1970s, numerous advances in equipment and adjuvant medical treatment have progressively improved the technical success of the procedure, the number of lesions amenable to revascularization, and the durability of revascularization with a substantial reduction in the incidence of coronary restenosis. As the potential of coated stents is realized,2 the goal of optimizing patient outcomes will not likely be restricted by limitations in attaining sustainable arterial patency, but on other patient factors that may limit the optimization of patients’ postrevascularization outcomes.
From the Mid America Heart Institute, St Luke’s Hospital, and, University of Missouri, Kansas City, Mo. Supported in part by unrestricted grants awarded by Pharmacia and the Agency for Healthcare Research and Quality (AHRQ R01HS11282-01). Submitted March 4, 2002; accepted July 12, 2002. Reprint requests: C. Keith Haddock, PhD, Cardiovascular Research, Mid America Heart Institute, St. Luke’s Hospital, 4401 Wornall Rd, Kansas City, MO 64111. E-mail: [email protected] Copyright 2003, Mosby, Inc. All rights reserved. 0002-8703/2003/$30.00 ⫹ 0 doi:10.1067/mhj.2003.67
Although some patient characteristics, such as age, are not modifiable, others are. One modifiable health behavior that is linked with poorer outcomes after PCI is cigarette smoking. For instance, patients who smoke typically require PCI significantly earlier in life than patients who do not smoke3 and have reduced exercise capacity and increased mortality rate after the procedure.4,5 Recently, one group examined the effect of smoking on the recovery of health status. Taira et al6 prospectively examined health status in 1432 patients who underwent PCI in either of 2 clinical trials.7 By use of the Medical Outcomes Study Short-Form 36 (SF36), they demonstrated that patients who do not smoke experienced significantly greater health status gains from PCI than patients who smoke. This was the first study to demonstrate that the health status benefits of PCI are diminished by continued smoking.6 We sought to both validate this earlier study in a consecutive cohort of patients (as opposed to the selected population of a clinical trial) and to further explore the impact of smoking on disease-specific health status. In particular, we sought to define the impact of smoking on the alleviation of symptoms, on the physical limitations caused by angina, and on patients’ perceptions of how their coronary disease affects their
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Table I. Baseline participant characteristics Smoking Status
Variables
Never smokers (n ⴝ 45)
Ex-smokers (n ⴝ 121)
Current smokers (n ⴝ 100)
66.12 46.5 94.9 71.7 82.7
65.61 19.8 93.3 81.0 82.6
55.31 37.8 93.2 62.2 84.4
29.7 27.7 74.5 2.03 54.3 42.6 52.1
30.3 31.1 72.3 2.13 55.5 43.2 70.6
29.1 20.5 50.0 1.84 54.5 56.8 38.6
12.6 3.2
15.7 3.4
7.9 0.0
Demographic variables Mean age* Sex (% female)* Ethnicity (% white) Marital status (% married)* Education (% high school or greater) Clinical and disease severity variables Mean body mass index (kg/m2) Diabetes (% yes) Hypertension (% yes)* Mean number of diseased vessels Previous MI (% yes) Angina type (% unstable) Prior coronary bypass graft or PCI in past 6 months (% yes)* Ejection fraction (% ⬍40) Preoperative creatinine level (% ⬎2) *Statistically significant differences among smoking status group (P ⬍ .05).
quality of life. Because most patients who smoke continue to smoke after PCI, understanding the limitations of coronary interventions on improving their outcomes—specifically those for which the procedure is performed in the first place—may be an important component of clinical decision-making.8
month ago; 4) Currently smoke less than 1 pack per day; 5) Currently smoke more than 1 pack per day; 6) Currently smoke more than 2 packs per day.” Participants who selected response “1” were termed never smokers; participants who selected response “2” were labeled ex-smokers, whereas participants who selected responses “3” through “6” were categorized as current smokers (ie, past 30-day smoking).
Methods
Outcomes measures
Participants
Generic health status: The Short-Form-12. The SF-36 originally was developed to assess psychological and physical functioning, including limitations in physical activities because of health problems, limitations in social function, limitations in usual role activities because of physical or emotional problems, bodily pain, general mental health, vitality, and general health perceptions.10 Ware et al7 used regression models to select 12 items from the SF-36 that could be used to approximate the SF-36 physical and mental component summary scores. The physical and mental component scores are transformed to facilitate their interpretation so that a score of 50 represents the US population mean and each 10point deviation from 50 represents 1 SD.
The Mid-America Heart Institute of St Luke’s Hospital in Kansas City, Mo, enrolled 271 consecutive patients undergoing PCI from February 8, 1999, to April 23, 1999. Patients were eligible when they spoke English and were aged ⱖ18 years. The process of patient recruitment, mechanism, success, and potential selection biases of baseline health status data collection have been previously described.9 In brief, patients were asked to participate in an observational research study documenting the recovery of their health status after coronary revascularization. Patients who consented were administered questionnaires at baseline, 6 months, and 1 year that included several health-status instruments and a range of sociodemographic questions. These data were used to supplement an existing procedural database. Approval from the St Luke’s Hospital Institutional Review Board was obtained before the conduction of this study. Appropriate informed consent was obtained from all participants before entry into the study.
Definition of smoking status categories Patients were asked, “Which of the following best describes your smoking history? 1) Have never smoked; 2) Stopped more than 1 month ago; 3) Stopped less than 1
Disease-specific health status: Seattle Angina Questionnaire. The Seattle Angina Questionnaire (SAQ) is a disease-
specific health status measure for patients with coronary artery disease. The SAQ is a 19-item, self-administered survey designed to assess 5 clinically relevant domains of coronary disease: physical limitations, anginal stability, anginal frequency, treatment satisfaction, and quality of life.11 Each of the 5 SAQ scales has explicitly and independently been demonstrated to be valid, reliable, and responsive to clinical change.11-14 For this study, only the SAQ physical limitation, angina frequency, and quality of life domains were used. These 3 scales
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654 Haddock et al
Table II. Health-related functional status and quality of life after percutaneous coronary intervention Baseline
Variables SAQ Physical limitations Angina frequency Quality of life SF-12 Physical component Mental component
6 months
Never smokers
Ex-smokers
Current smokers
Never smokers
Ex-smokers
Current smokers
67.79 (26.89) 62.55 (29.18) 50.46 (23.35)
70.10 (24.05) 58.83 (27.85) 52.44 (21.91)
62.68 (28.91) 63.49 (26.08) 48.39 (20.83)
73.82 (25.31) 84.78 (22.45) 79.86 (23.18)
81.47 (20.65) 85.33 (20.40) 77.98 (22.51)
66.43 (22.76) 83.33 (20.94) 72.02 (22.25)
38.23 (11.70) 48.63 (10.76)
36.68 (10.43) 48.36 (9.92)
36.68 (10.94) 45.63 (9.51)
40.65 (12.04) 51.44 (9.95)
40.38 (12.16) 52.28 (9.19)
35.48 (12.59) 45.98 (10.92)
All models include adjustment for age, sex, marital status, hypertension, number of diseased vessels, ejection fraction ⬍40%, preoperative creatinine level ⬎2, and baseline assessment score. Smokers n ⫽ 45. Ex-smokers n ⫽ 121. Never smokers n ⫽ 100.
Figure 1
Health-related functional status and quality of life after PCI.
are the most clinically interpretable and are typically used to examine the clinical benefits of treatment. Domain scores are transformed to a 0- to 100-scale by subtracting the lowest possible scale score, dividing by the range, and multiplying by 100. Higher scores are indicative of better functioning, whereas lower scores indicate worse health status (eg, greater frequency of angina, more physical limitations, and worse quality of life).11,13 12-Month mortality. Survival status of patients not interviewed at 12 months was assessed by querying the National Death Index and hospital records.
Statistical analyses Risk-adjusted analysis of covariance models were used to evaluate the impact of smoking category on disease-specific
(SAQ) and generic (SF-36) health status at 6 and 12 months. All models that examined health status at the 2 follow-up periods were adjusted for relevant demographic factors (eg, age, sex, marital status, education, minority status), indicators of disease severity (eg, body mass index, prior MI or revascularization, diabetes mellitus, hypertension, the number of diseased vessels, an ejection fraction ⬍40%, and preoperative creatinine level ⬎2), and the patient’s baseline SF-36 or SAQ domain score. When the risk-adjusted analysis of covariance models identified a significant group (ie, smoking status) effect, post hoc tests were conducted with the least significant difference test. The relationship of 12-month mortality rate and smoking status was examined by use of the 2 test. Statistical significance was defined as a 2-sided P value ⱕ.05.
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Haddock et al 655
6 months
12 months
P value
Never smokers
Ex-smokers
Current smokers
F value
P value
4.08 .575 .022
.019 .564 .978
86.02 (19.97) 91.90 (17.68) 84.08 (19.15)
89.36 (16.81) 92.77 (13.37) 86.42 (13.91)
69.95 (27.13) 78.57 (30.05) 70.08 (23.94)
3.94 4.21 5.91
.022 .017 .003
4.48 .433
.013 .649
42.65 (12.37) 54.89 (7.50)
41.20 (12.54) 55.18 (7.81)
30.35 (11.15) 50.77 (8.65)
8.54 .538
.000 .585
F value
Results Of the 271 patients who agreed to participate, 266 patients undergoing PCI (98.2%) provided data about their smoking status at baseline (current smokers [n ⫽ 45], ex-smokers [n ⫽ 121], never smokers [n ⫽ 100]). Within this sample, 233 patients (87.6%) and 210 patients (78.9%) completed the 6- and 12-month, respectively, follow-up assessments or were confirmed as deceased. With a logistic modeling procedure, we examined the odds of drop out at 12 months by using relevant demographic factors (eg, sex, income, ethnicity), cardiovascular risk factors (eg, diabetes mellitus, ejection fraction, creatinine level, hypertension), and smoking status. Participation in the follow-up assessment was not significantly related to smoking status, but was related to sex (men less likely to participate, P ⫽ .016) and marital status (unmarried individuals less likely to participate, P ⫽ .029). Table I presents the characteristics of the patients with PCI, stratified by smoking status. Smoking status was related to 3 of the 5 demographic factors: age, sex, and marital status. Patients who smoked were significantly younger than other patients, with a mean age at the time of revascularlization that was more than a decade younger than patients who never smoked and patients who were former smokers. Also, fewer patients who were former smokers were female and were married than members of the other patient groups. For clinical characteristics, patients who smoked were less likely to have a history of hypertension or a prior revascularization than other patients, possibly because of their relatively young age. Table II presents the health status outcomes for patients receiving PCI at baseline, 6 months, and 12 months, stratified by smoking status. These data are also presented visually in Figure 1.
Impact of smoking on mortality The smoking status groups experienced similar rates of mortality at 12 months, with 6.4% of the never
smokers group, 5.9% of ex-smokers group, and 6.7% of current smokers group dying in the year after revascularization. These differences were not statistically significant (2 ⫽ 0.035, P ⫽ .983).
Impact of smoking on generic health status after PCI Smoking status was associated with the physical component score of the SF-12 at 6 months after revascularization. Specifically, patients in the ex-smokers group reported fewer overall physical limitations than patients in the current smoker group (physical component score 40.6 ⫾ 12.0 vs 35.5 ⫾ 12.6, P ⫽ .013). At the 12-month assessment, patients in the never smokers and ex-smokers group still scored significantly higher than patients in the current smokers group on the physical component of the SF-12, which indicated a better sense of general physical quality of life (physical component score 42.7 ⫾ 12.4 and 41.2 ⫾ 12.5 vs 30.4 ⫾ 11.1, P ⬍ .001 for both comparisons). Little impact of smoking on the SF-36 mental component scores was observed at either 6 or 12 months.
Impact of smoking on disease-specific health status after PCI Smoking status was associated with SAQ scores at 6 and 12 months. Six months after their procedure, patients who were smokers had significantly more physical limitations because of angina than patients who did not smoke (SAQ physical limitation score 66.4 ⫾ 22.8 vs 73.8 ⫾ 25.3 for nonsmokers and 81.5 ⫾ 20.7 for ex-smokers, P ⫽ .02). With time, differences in the disease-specific health status of patients in the current smokers group and other patients became more pronounced. Twelve months after PCI, patients in the never smokers and ex-smokers group scored significantly higher on all 3 SAQ subdomains than patients in the current smokers group. The SAQ physical limitation scores of patients in the current smokers group were significantly lower than patients in the never
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656 Haddock et al
smokers (70.0 ⫾ 27.1 vs 86.0 ⫾ 20, P ⫽ .02) and exsmokers groups (70.0 ⫾ 27.1 vs 89.4 ⫾ 16.8, P ⫽ .007). The SAQ angina frequency scores of patients in the current smokers group were significantly lower than patients in the never smokers (78.6 ⫾ 30.0 vs 91.9 ⫾ 17.7, P ⫽ .002) and ex-smokers groups (78.6 ⫾ 30.0 vs 92.8 ⫾ 13.4, P ⫽ .006). The SAQ quality of life scores were also significantly lower for patients in the current smokers group than patients in the never smokers (70.1 ⫾ 23.9 vs 84.1 ⫾ 19.2, P ⫽ .011) and ex-smokers groups (70.1 ⫾ 23.9 vs 86.4 ⫾ 13.9, P ⫽ .001).
Discussion Because of the growing technical success of PCI, efforts at further improving patient outcomes need to extend beyond the cardiac catheterization laboratory. This study provides an important contribution to the medical literature by defining the blunted health status attained after PCI for patients who smoke compared with patients who never smoked or who had quit ⬎1 month before their procedure. Not only were the differences statistically significant, they were clinically large. For instance, patients who were nonsmokers (ie, never smokers and ex-smokers) reported SAQ anginal frequency scores that were ⬎20 points higher than patients who smoked. A difference of this magnitude is similar to that seen for the impact of PCI itself on SAQ anginal frequency scores.13 This increased frequency in angina resulted in significantly more physical-limitation on both the SAQ and SF-36 and in worse quality of life as assessed by the SAQ. Although smoking status was not related to mortality rate, patients who smoked were more than a decade younger at the time of intervention. Because patients who never smoked and who formerly smoked reported similar health-related quality of life after PCI, this study suggests (but does not prove) that patients who are smoking at the time of PCI might attain better results from the procedure if they quit ⬎1 month before undergoing revascularization. With the exception of PCI as a primary reperfusion strategy for myocardial infarction15 or in the treatment of unstable angina,16 PCI has not been shown to prolong survival; it is reasonable to consider delaying elective PCI until patients who smoke are able to quit. Patients with coronary disease severe enough to warrant revascularization are at a “teachable moment,” when smoking-cessation efforts can be implemented. With evidence clearly demonstrating that even brief smoking-cessation services can lead to significant rates of quitting, cardiologists should aggressively promote a tobacco-free lifestyle in their patients, perhaps even before revascularization.17 At a minimum, this might include receiving training in brief interventions on to-
bacco as part of regular continuing medical education, having office staff who are trained in tobacco-cessation techniques, and/or providing tailored (for factors such as culture and motivation to quit smoking) literature on tobacco cessation for patients.18 Also, clinical trials have demonstrated that nicotine replacement therapy (patch and gum) poses no risk for patients with active cardiovascular disease.19 Thus, cardiologists possess effective tools for treating nicotine dependence in their patients. In the early 1990s, British cardiologists debated about whether coronary artery bypass graft surgery should be routinely offered to patients who smoked because of the strong negative impact of tobacco use on the outcome of this intervention.20-22 Similarly, physicians in the United States were shown to be less likely to recommend coronary artery bypass graft surgery for patients with heart disease who smoked.23 Generally, cardiologists in the United States, Britain, and other developed countries offer cardiac care to patients regardless of smoking status. However, this paper adds to a growing literature that suggests smoking cessation should be aggressively pursued as part of routine cardiac care for patients with coronary artery disease. There are several limitations to this study. First, the participants in this study were largely white and educated (ie, high school or greater), and all participants were from a single high-volume coronary treatment center. Studies in more diverse samples would be needed before generalizing the findings to the general population of patients with cardiovascular disease. Second, smoking status was determined on the basis of self-report. Although self-reporting of smoking status is widely considered to be valid for observational studies such as this one,24-26 biochemical verification would improve the construct validity of the smoking-status measure. Finally, follow-up smoking status data were not collected as part of the observational study, so the effects of changes in smoking status on health status could not be examined. We currently are collecting detailed longitudinal data to determine the effects of smoking cessation on health status outcomes after PCI.
References 1. Smith SC, Dove JT, Jacobs AK, et al. ACC/AHA guidelines for percutaneous coronary (revision of the 1993 PTCA guidelines). J Am Coll Cardiol 2001;37:2215-39. 2. Hong MK, Kornowski R, Bramwell O, et al. Paclitaxel-coated Gianturco-Roubin II (GR-II) stents reduce neointimal hyperplasia in a porcine coronary in-stent restenosis model. Coron Artery Dis 2001;12:513-5. 3. Violaris AG, Thury A, Regar E, et al. Influence of a history of smoking on short term (six months) clinical and angiographic outcome after successful coronary angioplasty. Heart 2000;84:299306.
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4. Hasdai DKN, Garratt KN, Grill DE, et al. Effect of smoking status on the long-term outcome after successful percutaneous coronary revascularization. N Engl J Med 1997;336:755-61. 5. Jorgensen B, Endresen K, Forfang K, et al. Attenuated physical exercise capacity in smokers compared with non-smokers after coronary angioplasty despite similar luminal diameters. Eur Heart J 1998;19:737-41. 6. Taira DA, Seto TB, Ho KK, et al. Impact of smoking on health-related quality of life after percutaneous coronary revascularization. Circulation 2000;102:1369-74. 7. Ware JE, Snow KK, Kosinski M, et al. SF-36 health survey: manual and interpretation guide. Boston (Mass): The Health Institute, New England Medical Center; 1993. 8. Attebring MF, Hartford M, Holm G, et al. Risk indicators for recurrence among patients with coronary artery disease: problems associated with their modification. Scand Cardiovasc J 1998;32:916. 9. Spertus JA, Bliven BD, Farner M, et al. Integrating baseline health status data collection into the process of care. Jt Comm J Qual Improv 2001;27:369-80. 10. McHorney CA, Ware JE Jr, Raczek AE. The MOS 36-Item ShortForm Health Survey (SF-36): II: psychometric and clinical tests of validity in measuring physical and mental health constructs. Med Care 1993;31:247-63. 11. Spertus JA, Winder JA, Dewhurst TA, et al. Monitoring the quality of life in patients with coronary artery disease. Am J Cardiol 1994;74:1240-4. 12. Dougherty CM, Newhurst T, Nichol WP, et al. Comparison of three quality of life instruments in stable angina pectoris: Seattle Angina Questionnaire, Short Form Health Survey (SF-36), and Quality of Life Index-Cardiac Version III. J Clin Epidemiol 1998; 51:569-75. 13. Spertus J, Winder J, Dewhurst T, et al. Development and evaluation of the Seattle Angina Questionnaire: a new functional status measure for coronary artery disease. J Am Coll Cardiol 1995;25:333-41. 14. Deyo RA, Diehr P, Patrick DL. Reproducibility and responsiveness
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15.
16.
17.
18.
19. 20.
21. 22. 23. 24. 25.
26.
of health status measures: statistics and strategies for evaluation. Control Clin Trials 1991;12:14-58S. Cucherat M, Bonnefoy E, Tremeau G. Primary angioplasty versus intravenous thrombolysis for acute myocardial infarction [computer file]. Cochrane Database Syst Rev 2000;2:CD001560. Cannon CP, Weintraub WS, Demopoulos LA, et al. Comparison of early invasive and conservative strategies in patients with unstable coronary syndromes treated with the glycoprotein Iib/IIIa inhibitor triofiban. N Engl J Med 2001;344;1879-87. Fiore MC, Bailey WC, Cohen SJ, et al. Treating tobacco use and dependence. Clinical Practice Guideline. Rockville (Md): US Department of Health and Human Services, Public Health Service; June 2000. Stein RJ, Haddock CK, O’Byrne KK, et al. The pediatrician’s role in reducing tobacco exposure in children. Pediatrics 2000;106: e66. Benowitz NL. Treatment of nicotine dependence in clinical cardiology. CVD Prev 1999;2:135-9. Garfield J. Controversies in treatment: should smokers be offered coronary bypass surgery? Let the Health Authority take the responsibility [letter]. BMJ 1993;306:1050. Odom NJ, Ashraf SS, Sharif MH, et al. Access to heart surgery for smokers. BMJ 1993;307:128-9. Underwood MJ, Bailey JS. Coronary bypass surgery should not be offered to smokers. BMJ 1993;306:1047-9. Mogielnicki RP, Bell J, Fowler FJ. The influence of patient smoking status on therapeutic decisions. J Gen Intern Med 1992;7:165-9. Velicer WF, Prochaska JO, Rossi JS, et al. Assessing outcome in smoking cessation studies. Psychol Bull 1992;111:23-41. Glasgow RE, Mullooly JP, Vogt TM, et al. Biochemical validation of smoking status in public health settings: pros, cons, and data from four low intensity interventions trials. Addict Behav 1992;18: 504-27. Patrick DL, Cheadle A, Thompson DC, et al. The validity of selfreported smoking: a review and meta-analysis. Am J Public Health 1994;84:1086-93.
Smoking and health outcomes after percutaneous coronary intervention C. Keith Haddock, PhD, Walker S. C. Poston, PhD, Jennifer E. Taylor, MA, Mark Conard, MA, and John Spertus, MD, MPH, FACC Kansas City, Mo
Background This study was designed to describe the impact of smoking on health status and mortality after percutaneous coronary intervention (PCI).
Methods A cohort of 271 consecutive PCI patients at the Mid-America Heart Institute of St Luke’s Hospital in Kansas City, Mo, were observed in a prospective, observational study. Surveys that included health status assessments were administered at baseline and at 6 and 12 months after intervention. Primary outcome was health status as measured by the Short Form-12 (SF-12) and the Seattle Angina Questionnaire (SAQ).
Results Risk-adjusted statistical models demonstrated that, across a number of health-related quality of life domains, patients who were current smokers had poorer health status outcomes than other patients after revascularization. For instance, patients who had never smoked (P ⬍ .001) and patients who were former smokers (P ⬍ .001) scored significantly higher than patients who were current smokers on the physical component score of the SF-12, which indicated a better sense of overall physical function. Similarly, patients who had never smoked and patients who were former smokers reported significantly fewer physical limitations, less angina, and a higher quality of life on the SAQ than patients who were current smokers. Smoking status was unrelated to mortality rate in the 12 months after revascularization. Conclusions Smoking substantially limits the potential health status benefits of PCI. (Am Heart J 2003;145:652-7.) Percutaneous coronary interventions (PCI) are a highly effective therapy in the treatment of coronary artery disease.1 Since the introduction of PCI in the late 1970s, numerous advances in equipment and adjuvant medical treatment have progressively improved the technical success of the procedure, the number of lesions amenable to revascularization, and the durability of revascularization with a substantial reduction in the incidence of coronary restenosis. As the potential of coated stents is realized,2 the goal of optimizing patient outcomes will not likely be restricted by limitations in attaining sustainable arterial patency, but on other patient factors that may limit the optimization of patients’ postrevascularization outcomes.
From the Mid America Heart Institute, St Luke’s Hospital, and, University of Missouri, Kansas City, Mo. Supported in part by unrestricted grants awarded by Pharmacia and the Agency for Healthcare Research and Quality (AHRQ R01HS11282-01). Submitted March 4, 2002; accepted July 12, 2002. Reprint requests: C. Keith Haddock, PhD, Cardiovascular Research, Mid America Heart Institute, St. Luke’s Hospital, 4401 Wornall Rd, Kansas City, MO 64111. E-mail: [email protected] Copyright 2003, Mosby, Inc. All rights reserved. 0002-8703/2003/$30.00 ⫹ 0 doi:10.1067/mhj.2003.67
Although some patient characteristics, such as age, are not modifiable, others are. One modifiable health behavior that is linked with poorer outcomes after PCI is cigarette smoking. For instance, patients who smoke typically require PCI significantly earlier in life than patients who do not smoke3 and have reduced exercise capacity and increased mortality rate after the procedure.4,5 Recently, one group examined the effect of smoking on the recovery of health status. Taira et al6 prospectively examined health status in 1432 patients who underwent PCI in either of 2 clinical trials.7 By use of the Medical Outcomes Study Short-Form 36 (SF36), they demonstrated that patients who do not smoke experienced significantly greater health status gains from PCI than patients who smoke. This was the first study to demonstrate that the health status benefits of PCI are diminished by continued smoking.6 We sought to both validate this earlier study in a consecutive cohort of patients (as opposed to the selected population of a clinical trial) and to further explore the impact of smoking on disease-specific health status. In particular, we sought to define the impact of smoking on the alleviation of symptoms, on the physical limitations caused by angina, and on patients’ perceptions of how their coronary disease affects their
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Table I. Baseline participant characteristics Smoking Status
Variables
Never smokers (n ⴝ 45)
Ex-smokers (n ⴝ 121)
Current smokers (n ⴝ 100)
66.12 46.5 94.9 71.7 82.7
65.61 19.8 93.3 81.0 82.6
55.31 37.8 93.2 62.2 84.4
29.7 27.7 74.5 2.03 54.3 42.6 52.1
30.3 31.1 72.3 2.13 55.5 43.2 70.6
29.1 20.5 50.0 1.84 54.5 56.8 38.6
12.6 3.2
15.7 3.4
7.9 0.0
Demographic variables Mean age* Sex (% female)* Ethnicity (% white) Marital status (% married)* Education (% high school or greater) Clinical and disease severity variables Mean body mass index (kg/m2) Diabetes (% yes) Hypertension (% yes)* Mean number of diseased vessels Previous MI (% yes) Angina type (% unstable) Prior coronary bypass graft or PCI in past 6 months (% yes)* Ejection fraction (% ⬍40) Preoperative creatinine level (% ⬎2) *Statistically significant differences among smoking status group (P ⬍ .05).
quality of life. Because most patients who smoke continue to smoke after PCI, understanding the limitations of coronary interventions on improving their outcomes—specifically those for which the procedure is performed in the first place—may be an important component of clinical decision-making.8
month ago; 4) Currently smoke less than 1 pack per day; 5) Currently smoke more than 1 pack per day; 6) Currently smoke more than 2 packs per day.” Participants who selected response “1” were termed never smokers; participants who selected response “2” were labeled ex-smokers, whereas participants who selected responses “3” through “6” were categorized as current smokers (ie, past 30-day smoking).
Methods
Outcomes measures
Participants
Generic health status: The Short-Form-12. The SF-36 originally was developed to assess psychological and physical functioning, including limitations in physical activities because of health problems, limitations in social function, limitations in usual role activities because of physical or emotional problems, bodily pain, general mental health, vitality, and general health perceptions.10 Ware et al7 used regression models to select 12 items from the SF-36 that could be used to approximate the SF-36 physical and mental component summary scores. The physical and mental component scores are transformed to facilitate their interpretation so that a score of 50 represents the US population mean and each 10point deviation from 50 represents 1 SD.
The Mid-America Heart Institute of St Luke’s Hospital in Kansas City, Mo, enrolled 271 consecutive patients undergoing PCI from February 8, 1999, to April 23, 1999. Patients were eligible when they spoke English and were aged ⱖ18 years. The process of patient recruitment, mechanism, success, and potential selection biases of baseline health status data collection have been previously described.9 In brief, patients were asked to participate in an observational research study documenting the recovery of their health status after coronary revascularization. Patients who consented were administered questionnaires at baseline, 6 months, and 1 year that included several health-status instruments and a range of sociodemographic questions. These data were used to supplement an existing procedural database. Approval from the St Luke’s Hospital Institutional Review Board was obtained before the conduction of this study. Appropriate informed consent was obtained from all participants before entry into the study.
Definition of smoking status categories Patients were asked, “Which of the following best describes your smoking history? 1) Have never smoked; 2) Stopped more than 1 month ago; 3) Stopped less than 1
Disease-specific health status: Seattle Angina Questionnaire. The Seattle Angina Questionnaire (SAQ) is a disease-
specific health status measure for patients with coronary artery disease. The SAQ is a 19-item, self-administered survey designed to assess 5 clinically relevant domains of coronary disease: physical limitations, anginal stability, anginal frequency, treatment satisfaction, and quality of life.11 Each of the 5 SAQ scales has explicitly and independently been demonstrated to be valid, reliable, and responsive to clinical change.11-14 For this study, only the SAQ physical limitation, angina frequency, and quality of life domains were used. These 3 scales
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Table II. Health-related functional status and quality of life after percutaneous coronary intervention Baseline
Variables SAQ Physical limitations Angina frequency Quality of life SF-12 Physical component Mental component
6 months
Never smokers
Ex-smokers
Current smokers
Never smokers
Ex-smokers
Current smokers
67.79 (26.89) 62.55 (29.18) 50.46 (23.35)
70.10 (24.05) 58.83 (27.85) 52.44 (21.91)
62.68 (28.91) 63.49 (26.08) 48.39 (20.83)
73.82 (25.31) 84.78 (22.45) 79.86 (23.18)
81.47 (20.65) 85.33 (20.40) 77.98 (22.51)
66.43 (22.76) 83.33 (20.94) 72.02 (22.25)
38.23 (11.70) 48.63 (10.76)
36.68 (10.43) 48.36 (9.92)
36.68 (10.94) 45.63 (9.51)
40.65 (12.04) 51.44 (9.95)
40.38 (12.16) 52.28 (9.19)
35.48 (12.59) 45.98 (10.92)
All models include adjustment for age, sex, marital status, hypertension, number of diseased vessels, ejection fraction ⬍40%, preoperative creatinine level ⬎2, and baseline assessment score. Smokers n ⫽ 45. Ex-smokers n ⫽ 121. Never smokers n ⫽ 100.
Figure 1
Health-related functional status and quality of life after PCI.
are the most clinically interpretable and are typically used to examine the clinical benefits of treatment. Domain scores are transformed to a 0- to 100-scale by subtracting the lowest possible scale score, dividing by the range, and multiplying by 100. Higher scores are indicative of better functioning, whereas lower scores indicate worse health status (eg, greater frequency of angina, more physical limitations, and worse quality of life).11,13 12-Month mortality. Survival status of patients not interviewed at 12 months was assessed by querying the National Death Index and hospital records.
Statistical analyses Risk-adjusted analysis of covariance models were used to evaluate the impact of smoking category on disease-specific
(SAQ) and generic (SF-36) health status at 6 and 12 months. All models that examined health status at the 2 follow-up periods were adjusted for relevant demographic factors (eg, age, sex, marital status, education, minority status), indicators of disease severity (eg, body mass index, prior MI or revascularization, diabetes mellitus, hypertension, the number of diseased vessels, an ejection fraction ⬍40%, and preoperative creatinine level ⬎2), and the patient’s baseline SF-36 or SAQ domain score. When the risk-adjusted analysis of covariance models identified a significant group (ie, smoking status) effect, post hoc tests were conducted with the least significant difference test. The relationship of 12-month mortality rate and smoking status was examined by use of the 2 test. Statistical significance was defined as a 2-sided P value ⱕ.05.
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Haddock et al 655
6 months
12 months
P value
Never smokers
Ex-smokers
Current smokers
F value
P value
4.08 .575 .022
.019 .564 .978
86.02 (19.97) 91.90 (17.68) 84.08 (19.15)
89.36 (16.81) 92.77 (13.37) 86.42 (13.91)
69.95 (27.13) 78.57 (30.05) 70.08 (23.94)
3.94 4.21 5.91
.022 .017 .003
4.48 .433
.013 .649
42.65 (12.37) 54.89 (7.50)
41.20 (12.54) 55.18 (7.81)
30.35 (11.15) 50.77 (8.65)
8.54 .538
.000 .585
F value
Results Of the 271 patients who agreed to participate, 266 patients undergoing PCI (98.2%) provided data about their smoking status at baseline (current smokers [n ⫽ 45], ex-smokers [n ⫽ 121], never smokers [n ⫽ 100]). Within this sample, 233 patients (87.6%) and 210 patients (78.9%) completed the 6- and 12-month, respectively, follow-up assessments or were confirmed as deceased. With a logistic modeling procedure, we examined the odds of drop out at 12 months by using relevant demographic factors (eg, sex, income, ethnicity), cardiovascular risk factors (eg, diabetes mellitus, ejection fraction, creatinine level, hypertension), and smoking status. Participation in the follow-up assessment was not significantly related to smoking status, but was related to sex (men less likely to participate, P ⫽ .016) and marital status (unmarried individuals less likely to participate, P ⫽ .029). Table I presents the characteristics of the patients with PCI, stratified by smoking status. Smoking status was related to 3 of the 5 demographic factors: age, sex, and marital status. Patients who smoked were significantly younger than other patients, with a mean age at the time of revascularlization that was more than a decade younger than patients who never smoked and patients who were former smokers. Also, fewer patients who were former smokers were female and were married than members of the other patient groups. For clinical characteristics, patients who smoked were less likely to have a history of hypertension or a prior revascularization than other patients, possibly because of their relatively young age. Table II presents the health status outcomes for patients receiving PCI at baseline, 6 months, and 12 months, stratified by smoking status. These data are also presented visually in Figure 1.
Impact of smoking on mortality The smoking status groups experienced similar rates of mortality at 12 months, with 6.4% of the never
smokers group, 5.9% of ex-smokers group, and 6.7% of current smokers group dying in the year after revascularization. These differences were not statistically significant (2 ⫽ 0.035, P ⫽ .983).
Impact of smoking on generic health status after PCI Smoking status was associated with the physical component score of the SF-12 at 6 months after revascularization. Specifically, patients in the ex-smokers group reported fewer overall physical limitations than patients in the current smoker group (physical component score 40.6 ⫾ 12.0 vs 35.5 ⫾ 12.6, P ⫽ .013). At the 12-month assessment, patients in the never smokers and ex-smokers group still scored significantly higher than patients in the current smokers group on the physical component of the SF-12, which indicated a better sense of general physical quality of life (physical component score 42.7 ⫾ 12.4 and 41.2 ⫾ 12.5 vs 30.4 ⫾ 11.1, P ⬍ .001 for both comparisons). Little impact of smoking on the SF-36 mental component scores was observed at either 6 or 12 months.
Impact of smoking on disease-specific health status after PCI Smoking status was associated with SAQ scores at 6 and 12 months. Six months after their procedure, patients who were smokers had significantly more physical limitations because of angina than patients who did not smoke (SAQ physical limitation score 66.4 ⫾ 22.8 vs 73.8 ⫾ 25.3 for nonsmokers and 81.5 ⫾ 20.7 for ex-smokers, P ⫽ .02). With time, differences in the disease-specific health status of patients in the current smokers group and other patients became more pronounced. Twelve months after PCI, patients in the never smokers and ex-smokers group scored significantly higher on all 3 SAQ subdomains than patients in the current smokers group. The SAQ physical limitation scores of patients in the current smokers group were significantly lower than patients in the never
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656 Haddock et al
smokers (70.0 ⫾ 27.1 vs 86.0 ⫾ 20, P ⫽ .02) and exsmokers groups (70.0 ⫾ 27.1 vs 89.4 ⫾ 16.8, P ⫽ .007). The SAQ angina frequency scores of patients in the current smokers group were significantly lower than patients in the never smokers (78.6 ⫾ 30.0 vs 91.9 ⫾ 17.7, P ⫽ .002) and ex-smokers groups (78.6 ⫾ 30.0 vs 92.8 ⫾ 13.4, P ⫽ .006). The SAQ quality of life scores were also significantly lower for patients in the current smokers group than patients in the never smokers (70.1 ⫾ 23.9 vs 84.1 ⫾ 19.2, P ⫽ .011) and ex-smokers groups (70.1 ⫾ 23.9 vs 86.4 ⫾ 13.9, P ⫽ .001).
Discussion Because of the growing technical success of PCI, efforts at further improving patient outcomes need to extend beyond the cardiac catheterization laboratory. This study provides an important contribution to the medical literature by defining the blunted health status attained after PCI for patients who smoke compared with patients who never smoked or who had quit ⬎1 month before their procedure. Not only were the differences statistically significant, they were clinically large. For instance, patients who were nonsmokers (ie, never smokers and ex-smokers) reported SAQ anginal frequency scores that were ⬎20 points higher than patients who smoked. A difference of this magnitude is similar to that seen for the impact of PCI itself on SAQ anginal frequency scores.13 This increased frequency in angina resulted in significantly more physical-limitation on both the SAQ and SF-36 and in worse quality of life as assessed by the SAQ. Although smoking status was not related to mortality rate, patients who smoked were more than a decade younger at the time of intervention. Because patients who never smoked and who formerly smoked reported similar health-related quality of life after PCI, this study suggests (but does not prove) that patients who are smoking at the time of PCI might attain better results from the procedure if they quit ⬎1 month before undergoing revascularization. With the exception of PCI as a primary reperfusion strategy for myocardial infarction15 or in the treatment of unstable angina,16 PCI has not been shown to prolong survival; it is reasonable to consider delaying elective PCI until patients who smoke are able to quit. Patients with coronary disease severe enough to warrant revascularization are at a “teachable moment,” when smoking-cessation efforts can be implemented. With evidence clearly demonstrating that even brief smoking-cessation services can lead to significant rates of quitting, cardiologists should aggressively promote a tobacco-free lifestyle in their patients, perhaps even before revascularization.17 At a minimum, this might include receiving training in brief interventions on to-
bacco as part of regular continuing medical education, having office staff who are trained in tobacco-cessation techniques, and/or providing tailored (for factors such as culture and motivation to quit smoking) literature on tobacco cessation for patients.18 Also, clinical trials have demonstrated that nicotine replacement therapy (patch and gum) poses no risk for patients with active cardiovascular disease.19 Thus, cardiologists possess effective tools for treating nicotine dependence in their patients. In the early 1990s, British cardiologists debated about whether coronary artery bypass graft surgery should be routinely offered to patients who smoked because of the strong negative impact of tobacco use on the outcome of this intervention.20-22 Similarly, physicians in the United States were shown to be less likely to recommend coronary artery bypass graft surgery for patients with heart disease who smoked.23 Generally, cardiologists in the United States, Britain, and other developed countries offer cardiac care to patients regardless of smoking status. However, this paper adds to a growing literature that suggests smoking cessation should be aggressively pursued as part of routine cardiac care for patients with coronary artery disease. There are several limitations to this study. First, the participants in this study were largely white and educated (ie, high school or greater), and all participants were from a single high-volume coronary treatment center. Studies in more diverse samples would be needed before generalizing the findings to the general population of patients with cardiovascular disease. Second, smoking status was determined on the basis of self-report. Although self-reporting of smoking status is widely considered to be valid for observational studies such as this one,24-26 biochemical verification would improve the construct validity of the smoking-status measure. Finally, follow-up smoking status data were not collected as part of the observational study, so the effects of changes in smoking status on health status could not be examined. We currently are collecting detailed longitudinal data to determine the effects of smoking cessation on health status outcomes after PCI.
References 1. Smith SC, Dove JT, Jacobs AK, et al. ACC/AHA guidelines for percutaneous coronary (revision of the 1993 PTCA guidelines). J Am Coll Cardiol 2001;37:2215-39. 2. Hong MK, Kornowski R, Bramwell O, et al. Paclitaxel-coated Gianturco-Roubin II (GR-II) stents reduce neointimal hyperplasia in a porcine coronary in-stent restenosis model. Coron Artery Dis 2001;12:513-5. 3. Violaris AG, Thury A, Regar E, et al. Influence of a history of smoking on short term (six months) clinical and angiographic outcome after successful coronary angioplasty. Heart 2000;84:299306.
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4. Hasdai DKN, Garratt KN, Grill DE, et al. Effect of smoking status on the long-term outcome after successful percutaneous coronary revascularization. N Engl J Med 1997;336:755-61. 5. Jorgensen B, Endresen K, Forfang K, et al. Attenuated physical exercise capacity in smokers compared with non-smokers after coronary angioplasty despite similar luminal diameters. Eur Heart J 1998;19:737-41. 6. Taira DA, Seto TB, Ho KK, et al. Impact of smoking on health-related quality of life after percutaneous coronary revascularization. Circulation 2000;102:1369-74. 7. Ware JE, Snow KK, Kosinski M, et al. SF-36 health survey: manual and interpretation guide. Boston (Mass): The Health Institute, New England Medical Center; 1993. 8. Attebring MF, Hartford M, Holm G, et al. Risk indicators for recurrence among patients with coronary artery disease: problems associated with their modification. Scand Cardiovasc J 1998;32:916. 9. Spertus JA, Bliven BD, Farner M, et al. Integrating baseline health status data collection into the process of care. Jt Comm J Qual Improv 2001;27:369-80. 10. McHorney CA, Ware JE Jr, Raczek AE. The MOS 36-Item ShortForm Health Survey (SF-36): II: psychometric and clinical tests of validity in measuring physical and mental health constructs. Med Care 1993;31:247-63. 11. Spertus JA, Winder JA, Dewhurst TA, et al. Monitoring the quality of life in patients with coronary artery disease. Am J Cardiol 1994;74:1240-4. 12. Dougherty CM, Newhurst T, Nichol WP, et al. Comparison of three quality of life instruments in stable angina pectoris: Seattle Angina Questionnaire, Short Form Health Survey (SF-36), and Quality of Life Index-Cardiac Version III. J Clin Epidemiol 1998; 51:569-75. 13. Spertus J, Winder J, Dewhurst T, et al. Development and evaluation of the Seattle Angina Questionnaire: a new functional status measure for coronary artery disease. J Am Coll Cardiol 1995;25:333-41. 14. Deyo RA, Diehr P, Patrick DL. Reproducibility and responsiveness
Haddock et al 657
15.
16.
17.
18.
19. 20.
21. 22. 23. 24. 25.
26.
of health status measures: statistics and strategies for evaluation. Control Clin Trials 1991;12:14-58S. Cucherat M, Bonnefoy E, Tremeau G. Primary angioplasty versus intravenous thrombolysis for acute myocardial infarction [computer file]. Cochrane Database Syst Rev 2000;2:CD001560. Cannon CP, Weintraub WS, Demopoulos LA, et al. Comparison of early invasive and conservative strategies in patients with unstable coronary syndromes treated with the glycoprotein Iib/IIIa inhibitor triofiban. N Engl J Med 2001;344;1879-87. Fiore MC, Bailey WC, Cohen SJ, et al. Treating tobacco use and dependence. Clinical Practice Guideline. Rockville (Md): US Department of Health and Human Services, Public Health Service; June 2000. Stein RJ, Haddock CK, O’Byrne KK, et al. The pediatrician’s role in reducing tobacco exposure in children. Pediatrics 2000;106: e66. Benowitz NL. Treatment of nicotine dependence in clinical cardiology. CVD Prev 1999;2:135-9. Garfield J. Controversies in treatment: should smokers be offered coronary bypass surgery? Let the Health Authority take the responsibility [letter]. BMJ 1993;306:1050. Odom NJ, Ashraf SS, Sharif MH, et al. Access to heart surgery for smokers. BMJ 1993;307:128-9. Underwood MJ, Bailey JS. Coronary bypass surgery should not be offered to smokers. BMJ 1993;306:1047-9. Mogielnicki RP, Bell J, Fowler FJ. The influence of patient smoking status on therapeutic decisions. J Gen Intern Med 1992;7:165-9. Velicer WF, Prochaska JO, Rossi JS, et al. Assessing outcome in smoking cessation studies. Psychol Bull 1992;111:23-41. Glasgow RE, Mullooly JP, Vogt TM, et al. Biochemical validation of smoking status in public health settings: pros, cons, and data from four low intensity interventions trials. Addict Behav 1992;18: 504-27. Patrick DL, Cheadle A, Thompson DC, et al. The validity of selfreported smoking: a review and meta-analysis. Am J Public Health 1994;84:1086-93.