Differentially classified methamphetamine-using men who have sex with men: A latent class analysis

Context: Substance use interventions for methamphetamine-using men who have sex with men (MSM) are limited by the assumption that they are a uniform group. We hypothesized that an LCA would identify distinct patterns of substance use and demographic and psychosocial variables associated with different substance-using groups would aid in understanding distinctions. Using cross-sectional data from 343 methamphetamine-using MSM, we conducted an LCA to model the patterns of polysubstance use then examined how the classes varied on psychosocial variables defined by the Information-Motivation-Behavioral Skills (IMB) model. Findings: Because we were interested in identifying patterns of polysubstance use (PSU) among our sample, we identified four classes: minimal PSU, marijuana PSU, cocaine/hallucinogens PSU, and designer drugs/heroin PSU. Men in the marijuana PSU class were less likely to have positive attitudes towards methamphetamine than participants in the other three classes. Men in the Cocaine and Hallucinogens PSU class were more likely to have higher PANAS scores (OR = 13.00 [3.25, 52.07]) compared to the other classes, and they were more likely to have higher self-efficacy to enact safer substance use strategies (OR = 10.72 [3.23, 35.47]). MSM in the Designer Drug and Heroin PSU class were more likely to have a diagnosis of Hepatitis B (OR = 4.07 [0.86, 19.36] despite having higher knowledge of sexual health practices (OR = 0.55 [0.36, 0.84]. Conclusions: Differential classification for methamphetamine-using MSM suggests an opportunity for tailored interventions and secondary prevention programs. By understanding how men vary on illicit substance use, interventionists can routinely screen and link men before they potentially progress to another classification.