Dennis Thomas, Michael J Abramson, Billie Bonevski, Johnson George

System change interventions for smoking cessation are policies and practices designed by organizations to integrate the identification of smokers and the subsequent offering of evidence-based nicotine dependence treatments into usual care. Such strategies have the potential to improve the provision of smoking cessation support in healthcare settings, and cessation outcomes among those who use them. To assess the effectiveness of system change interventions within healthcare settings, for increasing smoking cessation or the provision of smoking cessation care, or both. We searched databases including the Cochrane Tobacco Addiction Group Specialized Register, CENTRAL, MEDLINE, Embase, CINAHL, and PsycINFO in February 2016. We also searched clinical trial registries: WHO clinical trial registry, US National Institute of Health (NIH) clinical trial registry. We checked 'grey' literature, and handsearched bibliographies of relevant papers and publications. Randomized controlled trials (RCTs), cluster-RCTs, quasi-RCTs and interrupted time series studies that evaluated a system change intervention, which included identification of all smokers and subsequent offering of evidence-based nicotine dependence treatment. Using a standardized form, we extracted data from eligible studies on study settings, participants, interventions and outcomes of interest (both cessation and system-level outcomes). For cessation outcomes, we used the strictest available criteria to define abstinence. System-level outcomes included assessment and documentation of smoking status, provision of advice to quit or cessation counselling, referral and enrolment in quitline services, and prescribing of cessation medications. We assessed risks of bias according to the Cochrane Handbook and categorized each study as being at high, low or unclear risk of bias. We used a narrative synthesis to describe the effectiveness of the interventions on various outcomes, because of significant heterogeneity among studies. We included seven cluster-randomized controlled studies in this review. We rated the quality of evidence as very low or low, depending on the outcome, according to the GRADE standard. Evidence of efficacy was equivocal for abstinence from smoking at the longest follow-up (four studies), and for the secondary outcome 'prescribing of smoking cessation medications' (two studies). Four studies evaluated changes in provision of smoking cessation counselling and three favoured the intervention. There were significant improvements in documentation of smoking status (one study), quitline referral (two studies) and quitline enrolment (two studies). Other secondary endpoints, such as asking about tobacco use (three studies) and advising to quit (three studies), also indicated some positive effects. The available evidence suggests that system change interventions for smoking cessation may not be effective in achieving increased cessation rates, but have been shown to improve process outcomes, such as documentation of smoking status, provision of cessation counselling and referral to smoking cessation services. However, as the available research is limited we are not able to draw strong conclusions. There is a need for additional high-quality research to explore the impact of system change interventions on both cessation and system-level outcomes.