English

Abstract

Introduction: The use of pharmacological and behavioural therapies has been shown to help smokers quit. However, the efficacy of combining smoking cessation therapies remains poorly understood. We conducted a systematic review of randomized controlled trials (RCTs) with factorial designs to assess the efficacy of combination smoking cessation therapies. Methods: We performed a systematic search of the Cochrane Library, EMBASE, PsycINFO, and PubMed databases for RCTs of combination therapies for smoking cessation. We included RCTs with factorial designs,reporting biochemically validated point prevalence or continuous abstinence outcomes at 6 or 12 months. Combination therapies were either two pharmacotherapies or apharmacotherapy with behavioural therapy. Pharmacotherapies included nicotine replacement therapies (NRTs), bupropion, and varenicline. Behavioural therapies included counselling and minimal intervention. Results: A total of 11 RCTs met our inclusion criteria: 4 combinations of pharmacotherapies and 7 combinations of a pharmacotherapy with behavioural intervention. Combinations were two NRTs (2 RCTs), bupropion with NRT (3 RCTs), bupropion with behavioural intervention (4 RCTs), and NRT with behavioural intervention (3 RCTs). No identified trials combined varenicline with other included pharmacotherapies. Combining pharmacotherapies did not increase smoking abstinence at 6 or 12 months, compared with pharmacological monotherapies. Evidence suggests a modest yet inconsistent benefit from combining pharmacotherapy with behavioural therapy. Conclusion: Evidence from RCTs with factorial designs does not conclusively show combination smoking cessation therapies to be superior to monotherapies. Pharmacotherapies could be prescribed without behavioural therapy, with minimal loss of treatment efficacy. Key words: Smoking cessation, combination therapy, systematic review