Abstract: Thirty-five randomised controlled trials, one ongoing, involving 5796 participants met the criteria for inclusion in this review. Included studies assessed the efficacy of tobacco cessation interventions, including counselling, and pharmacotherapy consisting of nicotine replacement therapy (NRT) or non-NRT, or the two combined, in both inpatient and outpatient settings for participants in treatment and in recovery. Most studies did not report information to assess the risk of allocation, selection, and attrition bias, and were classified as unclear. Analyses considered the nature of the intervention, whether participants were in treatment or recovery and the type of dependency. Of the 34 studies included in the meta-analysis, 11 assessed counselling, 11 assessed pharmacotherapy, and 12 assessed counselling in combination with pharmacotherapy, compared to usual care or no intervention. Tobacco cessation interventions were significantly associated with tobacco abstinence for two types of interventions. Pharmacotherapy appeared to increase tobacco abstinence (RR 1.88, 95% CI 1.35 to 2.57, 11 studies, 1808 participants, low quality evidence), as did combined counselling and pharmacotherapy (RR 1.74, 95% CI 1.39 to 2.18, 12 studies, 2229 participants, low quality evidence) at the period of longest follow-up, which ranged from six weeks to 18 months. There was moderate evidence of heterogeneity (I2 = 56% with pharmacotherapy and 43% with counselling plus pharmacotherapy). Counselling interventions did not significantly increase tobacco abstinence (RR 1.33, 95% CI 0.90 to 1.95). Interventions were significantly associated with tobacco abstinence for both people in treatment (RR 1.99, 95% CI 1.59 to 2.50) and people in recovery (RR 1.33, 95% CI 1.06 to 1.67), and for people with alcohol dependence (RR 1.47, 95% CI 1.20 to 1.81) and people with other drug dependencies (RR 1.85, 95% CI 1.43 to 2.40). Offering tobacco cessation therapy to people in treatment or recovery for other drug dependence was not associated with a difference in abstinence rates from alcohol and other drugs (RR 0.97, 95% CI 0.91 to 1.03, 11 studies, 2231 participants, moderate evidence of heterogeneity (I2 = 66%)). Data on adverse effect of the interventions were limited. The studies included in this review suggest that providing tobacco cessation interventions targeted to smokers in treatment and recovery for alcohol and other drug dependencies increases tobacco abstinence. There was no evidence that providing interventions for tobacco cessation affected abstinence from alcohol and other drugs. The association between tobacco cessation interventions and tobacco abstinence was consistent for both pharmacotherapy and combined counselling and pharmacotherapy, for participants both in treatment and in recovery, and for people with alcohol dependency or other drug dependency. The evidence for the interventions was low quality due primarily to incomplete reporting of the risks of bias and clinical heterogeneity in the nature of treatment. Certain results were sensitive to the length of follow-up or the type of pharmacotherapy, suggesting that further research is warranted regarding whether tobacco cessation interventions are associated with tobacco abstinence for people in recovery, and the outcomes associated with NRT versus non-NRT or combined pharmacotherapy. Overall, the results suggest that tobacco cessation interventions incorporating pharmacotherapy should be incorporated into clinical practice to reduce tobacco addiction among people in treatment for or recovery from alcohol and other drug dependence.

Plain-language summary: We looked for studies that enrolled adult smokers who were either in treatment or had completed treatment for substance abuse, in hospital, outpatient or community settings and randomised them to either a treatment to help them stop smoking or a control. We last searched for evidence in August 2016. We found 34 published studies. The types of smoking cessation treatment tested included: counselling (which might be a brief advice session or multiple sessions of behavioural support, either individually or in a group); medicine (called pharmacotherapy; including any type of nicotine replacement therapy, with or without other medicines that help smokers to stop smoking); or a combination of counselling and pharmacotherapy. We combined the results of trials separately for each of these types of treatment, although different trials used different treatments. People who were in the control groups received usual care, brief advice about quitting smoking, or were put on a waiting list to receive treatment later. Most trials assessed the number of people who had quit smoking at least six months after beginning treatment although we also included some studies with a shorter time. Eleven studies with 1808 people tested the effects of various types of pharmacotherapy. There was evidence that people given pharmacotherapy were more successful at quitting smoking. Twelve studies with 2229 participants tested treatments that combined pharmacotherapy and counselling. There was evidence that people given combined treatments were more successful at quitting smoking. Eleven studies with 1759 people tested the effect of counselling compared to usual care. Combining these results did not show evidence of a benefit of counselling alone. Eleven studies with 2231 people reported whether people remained abstinent from alcohol and other drugs. Providing tobacco cessation interventions did not make people more likely to return to using alcohol or other drugs. We found no evidence that it made a difference whether people were given treatment to quit smoking when they were just starting treatment for other drug use or after they were in recovery. Results were also similar for people who were treated for alcohol use and for people who were treated for other drugs such as heroin. We judged the quality of the evidence to be low. Many studies did not give enough details about the methods that they used. The studies also considered very different types of treatment, making comparisons challenging.