Are long-term alcohol health harms overlooked in individuals with illicit drug problems? Alcohol-related morbidity and mortality in a Danish cohort of clients in residential rehabilitation for drug use disorders.

Aims: This study described the burden of alcohol-related morbidity and mortality among those who had been enrolled in residential treatment for drug use disorders in Denmark and investigated whether self-reported information on alcohol use provided at treatment admission can be used to assess risk for future serious alcohol-related harms.

Methods: At baseline (entry in drug use disorder treatment during 2000-10), clients completed a European adaptation of the Addiction Severity Index-5. We tracked 4981 clients through 2018 using multiple national registers to identify fully (100%) alcohol-attributable hospital contacts and deaths.

Results: The death rate due to fully alcohol-attributable causes was 411 per 100 000 person-years, with an average of 0.18 fully alcohol-attributable hospital contacts per person-year. Using the Addiction Severity Index-5 alcohol composite score as a predictor in an adjusted competing risks regression model, a higher score was associated with a higher risk of alcohol-related death. The alcohol composite score was a significant predictor of alcohol-related hospital contacts in an adjusted recurrent events model.

Conclusions: A substantial proportion of people originally identified as experiencing drug use disorders have alcohol problems that need to be monitored and managed to prevent serious complications. By demonstrating the predictive power of self-reported data, our study concludes that the Addiction Severity Index-5 can be used to identify individuals with drug use disorders at risk for severe long-term alcohol-related health outcomes.