Impact of Longitudinal Patterns of Alcohol Use on Mortality in People Who Inject Drugs: A Prospective,...

People who inject drugs (PWID) have higher mortality risks and excessive alcohol use compared with the general population. However, long-term alcohol usage trajectories' impacts on mortality outcomes among PWID are not well-established. We aim to characterize different longitudinal alcohol use patterns and evaluate their mortality outcomes among lifetime PWID.

Data are from our community-based, prospective cohort study of PWID in Baltimore, Maryland, United States. The analysis included participants from January 1, 2005, through February 29, 2020, who answered alcohol use screening questions at least once. We first performed group-based trajectory modeling to identify longitudinal patterns of alcohol use. Next, we applied time-to-event methods to assess the mortality risks associated with these patterns.

The analysis included 1935 participants. Five alcohol use patterns emerged: consistent high-risk use (7.1%), gradual decline from moderate-risk to lower-risk use (25.8%), faster decline from moderate-risk to minimal use (10.4%), consistent lower-risk use (28.6%), and minimal use (28.1%). Compared with high-risk use, faster decline [adjusted hazard ratio (aHR): 0.44 (95% CI: 0.30, 0.65)], lower-risk [aHR: 0.54 (95% CI: 0.39, 0.74)], and minimal [aHR: 0.58 (95% CI: 0.42, 0.80)] use each had a lower all-cause mortality risk. Furthermore, these 3 comparison groups also showed reduced noncommunicable disease-related mortality risks.

Relative to consistent high-risk alcohol use, alcohol reduction/cessation and long-term lower-risk or minimal alcohol use have lower all-cause and noncommunicable disease-related mortality risks. Our findings highlight the importance of alcohol use treatment services as a preventive health care strategy among lifetime PWID and other high-risk populations.