Gender differences in alcohol treatment: an analysis of outcome from the COMBINE study

Background: Relatively few studies have examined gender differences in the effectiveness of specific behavioral or pharmacologic treatment of alcohol dependence. The aim of this study is to assess whether there were gender differences in treatment outcomes for specific behavioral and medication treatments singly or in combination by conducting a secondary analysis of public access data from the national, multisite NIAAA-sponsored COMBINE study.

Methods: The COMBINE study investigated alcohol treatment among 8 groups of patients (378 women, 848 men) who received medical management (MM) with 16 weeks of placebo, naltrexone (100 mg/day), acamprosate (3 g/day), or their combination with or without a specialist-delivered combined behavioral intervention. We examined efficacy measures separately for men and women, followed by an overall analysis that included gender and its interaction with treatment condition in the analyses. These analyses were performed to confirm whether the findings reported in the parent trial were also relevant to women, and to more closely examine secondary outcome variables that were not analyzed previously for gender effects.

Results: Compared to men, women reported a later age of onset of alcohol dependence by approximately 3 years, were significantly less likely to have had previous alcohol treatment, and drank fewer drinks per drinking day. Otherwise, there were no baseline gender differences in drinking measures. Outcome analyses of 2 primary (percent days abstinent and time to first heavy drinking day) and 2 secondary (good clinical response and percent heavy drinking days) drinking measures yielded the same overall pattern in each gender as that observed in the parent COMBINE study report. That is, only the naltrexone by behavioral intervention interaction reached or approached significance in women as well as in men. There was a naltrexone main effect that was significant in both men and women in reduction in alcohol craving scores with naltrexone-treated subjects reporting lower craving than placebo-treated subjects.

Conclusions: This gender-focused analysis found that alcohol-dependent women responded to naltrexone with COMBINE's Medical Management, similar to the alcohol-dependent men, on a wide range of outcome measures. These results suggest that clinicians can feel comfortable prescribing naltrexone for alcohol dependence in both men and women. In this study, it is also notable that fewer women than men reported receiving any alcohol treatment prior to entry into the COMBINE study. Of note, women tend to go to primary health care more frequently than to specialty substance abuse programs for treatment, and so the benefit we confirm for women of the naltrexone and MM combination has practical implications for treating alcohol-dependent women.