Seventeen double-blind RCTs (4,087 participants) were included in the review.
No evidence of publication bias was reported. The trials scored between 65 and 83 on the Chalmers scale for study quality. Most aspects of trial design were well-executed. However, the drop-out rates were generally high (about 50%), and the proportion of individuals classified as abusers and dependent drinkers varied quite widely between trials (from 2 to 39%).
Treatment with acamprosate significantly increased continuous abstinence at 3, 6 and 12 months compared with placebo. The relative risk (RR) for continuous abstinence was 1.33 (95% confidence interval, CI: 1.20, 1.47) at 3 months and 1.47 (95% CI: 1.29, 1.69) at 6 months. However, whilst there was statistically significant variability between trials for this result, no significant effects for the covariates of age, severity of dependence, attrition rates, gender, sample size or the finding of no beneficial treatment effect were found. At 12 months, data on continuous abstinence were available from 5 trials (1,670 participants). Acamprosate was found to have a beneficial effect in both an intention-to-treat analysis (RR 1.95, 95% CI: 1.58, 2.42) and a per protocol analysis (RR 1.73, 95% CI: 1.41, 2.11).
Point prevalence abstinence at 6 and 12 months was also improved with acamprosate. The RR was 1.40 (95% CI: 1.24, 1.59) at 6 months and 1.62 (95% CI: 1.37, 1.92) at 12 months.
CADP was also significantly improved with acamprosate at 3, 6 and 12 months.
For acamprosate, the NNT to achieve one beneficial outcome was 7.78 at 6 months and 7.5 at 12 months.
Retention rates were significantly higher in acamprosate than placebo treatment groups.