Aims: To carry out a systematic review of the effectiveness of relapse prevention interventions (RPIs) among abstinent smokers who had completed an initial course of treatment or who had abstained unassisted, pooling only outcome data from similar follow-up time points.
Methods: We used the same search strategy as was used in Cochrane reviews of RPIs to identify randomized trials of behavioural and pharmacological studies of smoking RPIs published up to July 2008. Abstinence from smoking was defined as either continuous abstinence or point prevalence abstinence, measured at three follow-up time points: short term (1-3 months post randomization), medium term (6-9 months) and long term (12-18 months). Abstinence among pregnant/postpartum women was also measured at delivery or the last follow-up prior to delivery. Random effect meta-analysis was used to estimate pooled odds ratios (OR) with 95% confidence intervals (CI).
Results: Thirty-six studies randomizing abstainers were included. Self-help materials appeared to be effective in preventing relapse at long-term follow up in initially unaided quitters (pooled OR 1.52; 95% CI 1.15 to 2.01, I2 = 0%, NNT = 11, 3 studies). Other behavioural interventions for relapse prevention appeared effective in the short term only. There were positive results for the use of pharmacotherapies for relapse prevention. Bupropion was effective at long-term follow-up (pooled OR 1.49; 95% CI 1.10 to 2.01; I2 = 0%; NNT = 11; 4 studies). Nicotine replacement therapy (NRT) was effective at medium-term (pooled OR 1.56; 95% CI 1.16 to 2.11; I2 = 37%; NNT = 14; 4 trials) and long-term follow-ups (pooled OR 1.33; 95% CI 1.08 to 1.63; I2 = 0%; NNT = 20; 4 trials). Single trials of extended treatment of Varenicline and rimonabant were also found to be effective at short-term and medium-term follow-ups.
Conclusions: Self-help materials appear to prevent relapse in initially unaided quitters. Use of NRT, bupropion and varenicline appears to be effective in preventing relapse following an initial period of abstinence or an acute treatment episode. There is currently no good evidence that behavioural support prevents relapse after initial unaided abstinence or following an acute treatment period.