Objectives: To evaluate the effect of current smoking and lifetime illicit drug use on alcoholism treatment outcomes and to assess whether these factors influence acamprosate efficacy.
Methods: This is a secondary analysis of data from the intention-to-treat population (N = 601) in a 6-month, randomized, placebo-controlled US trial of acamprosate (2 or 3 g/d). Patients met Diagnostic and Statistical Manual of Mental Disorders, 4th Edition criteria for alcohol dependence and no other dependence disorders other than nicotine or cannabis, although patients with recent substance use were included. Baseline severities of current nicotine dependence and lifetime drug use were determined using the Fagerström test of nicotine dependence and the illicit drug use inventory, respectively. The primary endpoint was rate of good response (abstinence from alcohol for ≥90% of trial). Secondary endpoints were rate of controlled drinking (≤5 drinks/d for ≥90% of trial), percent days abstinent, and percent days controlled drinking. The effect of smoking, drug use, treatment, and any interactions on study endpoints was assessed by a backward selection process to eliminate nonsignificant variables.
Results: In the intention-to-treat population, 44.9% of patients were current smokers and 78.7% reported lifetime illicit drug use. Current nicotine dependence and lifetime illicit drug use were significant negative predictors of rates of good response (nicotine: odds ratio [OR] = 0.56, 95% confidence interval [CI] = 0.35–0.88, P = 0.01; illicit drugs: OR = 0.47, 95% CI = 0.31–0.71, P < 0.01) and all other secondary outcomes. Acamprosate had a significant positive effect on rate of good response (OR = 1.65, 95% CI = 1.08–2.52, P = 0.020) and all other secondary outcomes.
Conclusions: Current nicotine dependence and lifetime illicit drug use were found to have a significant negative impact on alcoholism treatment outcomes, but no impact on the significant positive effects of acamprosate. The effect sizes of smoking, drug use, and acamprosate are equivalent and thus, treatment with acamprosate may offset some of the negative effects of smoking or drug use on alcoholism treatment outcomes.