Exploring the impact of reduction in methamphetamine use on sexual risk behaviors among men who have sex with men and women: Findings from the ADAPT-2 trial.

Background: Methamphetamine (MA) use has been linked to engaging in sexual risk behaviors (SRBs) that are associated with HIV/STIs, particularly among men who have sex with men (MSM) and men who have sex with men and women (MSMW; hereafter MSM/W). The objectives of this analysis were to determine whether reduced MA is associated with decreases in SRBs in a sample of MSM/W.

Method: Data came from the ADAPT-2 trial, a randomized, double-blind, two-stage sequential parallel design trial evaluating extended-release injectable naltrexone (NTX) and oral bupropion (BUP) vs. placebo for MA use disorder. In the first 6 weeks of the trial (stage 1), participants were randomized to receive NTX-BUP or placebo. In the second 6 weeks, participants in the placebo group who did not have a treatment response were rerandomized (stage 2). For this secondary analysis, the independent variable was the number of MA-negative urine drug screens (UDS). The dependent variables included three different types of SRBs. Regression models of the independent and dependent variables were adjusted for age, race/ethnicity status, marital status, treatment assignment, and baseline SRBs.

Results: Of the 151 participants, median age was 40 years and majority were non-Hispanic white (52%) and completed more than high school education (82%). Each additional MA-negative UDS was associated with a 7% (adjusted rate ratio (aRR) =0.93; 95% CI, 0.87, 0.99) reduction in total number of sex partners in stage 2 only. Each additional MA-negative UDS was associated with a 13% (aRR =0.87 95%; confidence interval (CI), (0.76, 0.98)) and 9% (aRR =0.91; 95% CI, 0.84, 0.99) reduction in number of condomless sexual encounters in stage 1 and stage 2, respectively. Lastly, each additional MA-negative UDS was associated with a 16% (aRR =0.84; 95% (CI), 0.75, 0.94)) and 27% (aRR =0.73; 95% CI, 0.64, 0.84) reduction in number of sexual encounters when high on MA.

Conclusions: Our analysis showed that reductions in MA use was associated with reductions in several sexual risk behaviors associated with HIV/STI. These findings provide further support for exploring reductions in sexual risk behaviors as a clinical endpoint in future treatment interventions for MA use.

Related protocols: CTN-0068