Substance Use
Assessing associations between reduction in current substance use and HIV viral load in four diverse study populations using linear mixed models Ryan P. Kyle* Ryan Kyle Robin M. Nance Richard D. Moore Pamina M. Gorbach Brian S. Mustanski Shruti H. Mehta Marianna K. Baum Gregory D. Kirk Steven J. Shoptaw Laura Bamford Katerina A. Christopoulos George A. Yendewa Michael S. Saag Bridget M. Whitney Sonia Napravnik Joseph J. Eron Kenneth H. Mayer Peter W. Hunt Oluwaseun O. Falade-Nwulia Edward Cachay Geetanjali Chander Heidi M. Crane Joseph A.C. Delaney Raul N. Mandler Lydia N. Drumright
Background: Substance use is more prevalent among people with HIV (PWH) than in the general population, is associated with poor health outcomes, and is a barrier to effective care. PWH who use substances are less likely to achieve viral suppression, and are an important focus of efforts to control HIV transmission. Further, reduction, but not cessation, of substance use may be important to harm reduction efforts if it results in better HIV care.
Methods: In longitudinal analyses of data from the CNICS, JHHCC, RADAR, and mSTUDY cohorts, we assessed the association between HIV viral load, and use of methamphetamine, crack/cocaine, illicit opioids, marijuana, and alcohol using two-level linear mixed models to estimate relative viral load as a measure of the relative risk (RR) of exceeding varying thresholds for detection. Models clustered at the study and participant level to account for study heterogeneity and irregular data using an exchangeable correlation structure. All models were adjusted for baseline age, sex, race/ethnicity, study site, as well as time-varying frequency of other substance use.
Results: We identified 11,203 participants with at least two substance use measures. The mean follow-up was 3.8 years, 18% of participants were female, and the mean age was 45 years. Among PWH who reported illicit opioid use, PWH with reduced frequency of use had viral loads 39% lower than those not reporting stable or increased frequency of use (RR: 0.61; 95% CI: 0.39-0.94). Reduction in methamphetamine use was associated with 23% lower viral load (RR: 0.77; 95% CI: 0.60-0.99) on average relative to those with no reduction in current use. Quitting cocaine/crack (RR: 0.95; 95% CI: 0.79-1.15) or opioid use (RR: 0.91; 95% CI: 0.69-1.20) suggested an association with lower viral load. We did not find important associations between viral load and reductions in alcohol (RR: 0.99, 95% CI: 0.94-1.04) or cannabis use (RR: 1.05, 95% CI: 0.95-1.15).
Conclusions: Reduction in substance use over time among PWH was associated with lower relative viral load across all cohorts. As these analyses focused on frequency of use, and reasons for reductions in intensity of use were not explored, future work should also account for reasons PWH limit or cease use of substances, particularly in case of medication-assisted therapy and other interventions.