Social, Economic, and health risks among people who use Methamphetamine: Comparing three patterns of opioid Co-Use.

Objectives: To examine how persons using different methamphetamine-opioid combinations differ with respect to social, risk, and health characteristics, and to identify patterns of vulnerability across simultaneous, sequential, and independent use. Methods: 414 people who use illicit drugs were surveyed, 384 of whom reported polydrug use involving methamphetamine, in Nevada and New Mexico between June 2022 and August 2023. Participants were classified into three mutually exclusive groups based on self-reported methamphetamine and opioid use patterns: simultaneous use (deliberately using both drugs together), sequential use (using both drugs but not deliberately using simultaneously), and independent use (using methamphetamine alone or with non-opioid drugs). Prevalence ratios were calculated to examine associations between use patterns and social, economic, health, and drug use characteristics. Results: We identified three distinct use patterns: simultaneous (53.1%), sequential (17.7%), and independent (29.2%). Individuals in these risk groups exhibited differential social, economic, carceral, and health-related risk: those engaged in simultaneous showed higher vulnerability relative to people who use independently and sequentially. Healthcare engagement was associated with lower simultaneous use. Conclusions: These findings suggest the need to support development of strategies to support transition from higher to lower-risk drug use patterns.