How much does smoking cessation cut CHD risk?

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Clinical Inquiries

How much does smoking cessation cut CHD risk?

J Fam Pract. 2008 October;57(10):675-676

By

Shazia M. Frothingham, PhD

Patrick O. Smith, PhD

Thomas J. Payne, PhD

Susan E. Meadows, MLS

References

1. US Department of Health and Human Services. The Health Consequences of Smoking: What It Means to You. Atlanta, GA: US Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2004. Available at: www.cdc.gov/tobacco/data_statistics/sgr/sgr_2004/00_pdfs/SGR2004_Whatitmeanstoyou.pdf. Accessed September 9, 2008.

2. US Department of Health and Human Services. The Health Benefits of Smoking Cessation: A Report of the Surgeon General. Rockville, MD: US Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health. DHHS Publication No. (CDC) 90-8416;1990.

3. Critchley J, Capewell S. Smoking cessation for the secondary prevention of coronary heart disease. Cochrane Database Syst Rev. 2004;(1):CD003041.-

4. AHA ACC National Heart Lung and Blood Institute, et al. AHA/ACC guidelines for secondary prevention for patients with coronary and other atherosclerotic vascular disease: 2006 update endorsed by the National Heart, Lung, and Blood Institute. J Am Coll Cardiol. 2006;47:2130-2139.

5. Terry DF, Pencina MJ, Vasan RS, et al. Cardiovascular risk factors predictive for survival and morbidity-free survival in the oldest-old Framingham Heart Study participants. J Am Geriatr Soc. 2005;11:1944-1950.

6. Twardella D, Küpper-Nybelen J, Rothenbacher D, et al. Short-term benefit of smoking cessation in patients with coronary heart disease: estimates based on self-reported smoking data and serum cotinine measurements. Eur Heart J. 2004;25:2101-2108.

7. Cavender J, Rogers W, Fisher L, et al. for the CASS Investigators. Effects of smoking on survival and morbidity in patients randomized to medical or surgical therapy in the Coronary Artery Surgery Study (CASS): 10-year follow-up. J Am Coll Cardiol. 1992;20:287-294.

8. Van Domburg RT, Meeter K, van Berkel DF, et al. Smoking cessation reduces mortality after coronary artery bypass surgery: a 20-year follow-up study. J Am Coll Cardiol. 2000;36:878-883.

EVIDENCE-BASED ANSWER

Significantly. Patients with coronary heart disease (CHD) who refrain from smoking over a 2-year follow-up period decrease their relative risk (RR) for morbidity and mortality by about one third (strength of recommendation [SOR]: A, meta-analysis of 20 cohort studies). People who maintain abstinence after coronary artery bypass surgery are more likely to avoid angina, repeat revascularization, significant physical impairment, and CHD-related hospital admissions than patients who continue to smoke (SOR: A, 4 cohort studies with 1- to 20-year follow-up).

Evidence summary

FAST TRACK

Quitting smoking reduces overall mortality more than other secondary prevention measures, including aspirin, β-blockers, ACE inhibitors, and statins

The influence of cigarette smoking on the development of CHD has been well documented.^1,2 RR ranges from 1.5 to 3, depending on variables such as age, sex, and quantity of tobacco used.³ Quitting smoking reduces overall mortality more than other forms of secondary prevention, including aspirin, β-blockers, angiotensin-converting enzyme inhibitors, and cholesterol-lowering statins.³ In the wake of such evidence-based findings, the American Heart Association and American College of Cardiology Task Force developed clinical practice guidelines that recommend complete smoking cessation for secondary prevention of CHD in cardiac patients.⁴

0 cigarettes=lower mortality and morbidity

A Cochrane Heart Group meta-analysis examining all-cause CHD mortality in 20 cohort studies (n=12,603 patients), found a 36% reduction in mortality risk for CHD patients who quit smoking compared with those who didn’t (RR=0.64; 95% confidence interval [CI], 0.58-0.71).³ The review also noted a reduction in risk for nonfatal myocardial infarctions (RR=0.68; 95% CI, 0.57-0.82).³ The authors didn’t report how soon after smoking cessation mortality risk declined.

The authors acknowledge several limitations of the review, including the use of observational data and crude estimates, as well as potential publication bias and the misclassification of smoking status. Notably, however, their findings are consistent with the landmark prospective, community-based cohort Framingham Heart Study (N=1422), which indicates that smoking status predicts overall and morbidity-free survival at age 85.⁵

FAST TRACK

Patients with CHD who refrain from smoking for at least 2 years decrease their risk for morbidity and mortality by about one third

Smoking cessation has also been found to significantly affect morbidity among cardiac patients. Short-term benefits have been demonstrated in CHD patients after a myocardial infarction or coronary artery revascularization.⁶ Smoking status at 1-year follow-up was associated with a significant reduction in subsequent cardiac events (myocardial infarction, ischemic cerebrovascular event, revascularization, or death from CHD) when smokers who quit after an initial CHD event were compared with continuing smokers (odds ratio=0.71; 95% CI, 0.38-1.33).⁶

Evidence-based answers from the Family Physicians Inquiries Network

How much does smoking cessation cut CHD risk?

References

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