Characterizing Methamphetamine Use Among People Who Use Opioids: A Systematic Review

Methamphetamine use is increasing among people who use opioids (PWUO); however, factors associated with methamphetamine use among PWUO have not been systematically examined. We searched five electronic databases, from inception to January 3rd, 2023, for primary studies that characterized methamphetamine use and its associated risk factors among PWUO. We screened 3801 unique studies and included 33 quantitative primary studies. Two reviewers independently screened, extracted data, and assessed the risk of bias. Findings were narratively summarized. Eleven studies reported increasing trends of methamphetamine use among PWUO in the US and Canada. Twenty-eight studies conducted in North America and Asia examined factors associated with methamphetamine use among PWUO. Methamphetamine use was associated with younger age, residing in rural areas, lower socioeconomic status, mental and physical illnesses, and engaging in risky sexual and drug use behaviours. To combat the expanding "twin epidemic" of opioid and methamphetamine use, scaling up harm reduction interventions, supporting low-threshold addiction care, and investing in therapeutic options for methamphetamine use disorder is warranted.