Smoking cessation for secondary prevention of cardiovascular disease

• Published in: Cochrane database of systematic reviews 2022-08, Vol.8 (8), p.CD014936-CD014936
• Main Authors: Wu, Angela Difeng, Lindson, Nicola, Hartmann-Boyce, Jamie, Wahedi, Azizia, Hajizadeh, Anisa, Theodoulou, Annika, Thomas, Elizabeth T, Lee, Charlotte, Aveyard, Paul
• Format: Article
• Language: English
• Subjects: Adult; Cardiovascular Diseases - epidemiology; Cardiovascular Diseases - prevention & control; Coronary Disease - epidemiology; Coronary Disease - prevention & control; Humans; Myocardial Infarction - epidemiology; Myocardial Infarction - prevention & control; Quality of Life; Secondary Prevention; Smoking Cessation - methods; Stroke - epidemiology; Stroke - prevention & control; The effects of quitting smoking
• ISSN: 1469-493X
• DOI: 10.1002/14651858.CD014936.pub2

Smoking is a leading cause of cardiovascular disease (CVD), particularly coronary heart disease (CHD). However, quitting smoking may prevent secondary CVD events in people already diagnosed with CHD.  OBJECTIVES: To examine the impact of smoking cessation on death from CVD and major adverse cardiovascular events (MACE), in people with incident CHD. We searched the Cochrane Tobacco Addiction Group's Specialised Register, CENTRAL, MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature, and the trials registries clinicaltrials.gov and the International Clinical Trials Registry Platform. We ran all searches from database inception to 15 April 2021.  SELECTION CRITERIA: We included cohort studies, and both cluster- and individually randomised controlled trials of at least six months' duration. We treated all included studies as cohort studies and analysed them by smoking status at follow-up. Eligible studies had to recruit adults (> 18 years) with diagnosed CHD and who smoked tobacco at diagnosis, and assess whether they quit or continued smoking during the study. Studies had to measure at least one of our included outcomes with at least six months' follow-up. Our primary outcomes were death from CVD and MACE. Secondary outcomes included all-cause mortality, non-fatal myocardial infarction, non-fatal stroke, new-onset angina and change in quality of life.  DATA COLLECTION AND ANALYSIS: We followed standard Cochrane methods for screening and data extraction.  We assessed the risk of bias for the primary outcomes using the ROBINS-I tool. We compared the incidence of death from CVD and of MACE (primary outcomes) between participants who quit smoking versus those who continued to smoke for each included study that reported these outcomes. We also assessed differences in all-cause mortality, incidence of non-fatal myocardial infarction, incidence of non-fatal stroke and new onset angina. We calculated hazard ratios (HRs) and 95% confidence intervals (95% CI). For our outcome, change in quality of life, we calculated the pooled standardised mean difference (SMD) and 95% CI for the difference in change in quality of life from baseline to follow-up between those who had quit smoking and those who had continued to smoke. For all meta-analyses we used a generic inverse variance random-effects model and quantified statistical heterogeneity using the I²statistic. We assessed the certainty of evidence for our primary outcomes using the eight GRADE conside