Background: A number of clinical trials have been undertaken to determine the efficacy of acamprosate in the maintenance of abstinence in alcohol-dependent individuals. However, the reported differences in patient populations, treatment duration, and study endpoints make comparisons difficult. An assessment of the efficacy of treatment with acamprosate was, therefore, undertaken using meta-analytical techniques. Methods: All randomized, placebo-controlled trials (RCTs) that fulfilled predetermined criteria were identified using (1) a language unrestricted search of 10 electronic databases; (2) a manual search of relevant journals, symposia, and conference proceedings; (3) cross-referencing of all identified publications; (4) personal communications with investigators; and (5) scrutiny of Merck-Sante's internal reports of all European trials. Study quality was assessed, independently, by three blinded workers. Key outcome data were identified; some outcome variables were recalculated to ensure consistency across trials. The primary outcome measure was continuous abstinence at 6 months; abstinence rates were determined by estimating Relative Benefit (RB). Results: A total of 19 published 1 unpublished RCTs were identified that fulfilled the selection criteria; 3 were excluded because the documentation available was insufficient to allow adequate assessment. The remaining 17 studies, which included 4087 individuals, 53% of whom received active drug, were of good quality and were otherwise reasonably comparable. There was no evidence of publication bias. Continuous abstinence rates at 6 months were significantly higher in the acamprosate-treated patients (acamprosate, 36.1%; placebo, 23.4%; RB, 1.47; [95% confidence intervals (CI): 1.29-1.69];p < 0.001). This effect was observed independently of the method used for assigning missing data. The effect sizes in abstinent rates at 3, 6, and 12 months were 1.33, 1.50, and 1.95, respectively. At 12 months, the overall pooled difference in success rates between acamprosate and placebo was 13.3% (95% CI, 7.8-18.7%; number needed to treat, 7.5). Acamprosate also had a modest but significant beneficial effect on retention (6.01%; [95% CI, 2.90-8.82];p = 0.0106). Conclusion: Acamprosate has a significant beneficial effect in enhancing abstinence in recently detoxified, alcohol-dependent individuals.
