Background:
Persistent overdose mortality among people using multiple drugs necessitates further investigation into polysubstance use patterns and determinants. Emerging data implicate combinations of opioids and stimulants in elevated mortality, though relatively little is known about if and how people who use drugs (PWUD) transition between patterns of opioid-stimulant use over time.
Methods:
We used longitudinal data from a prospective cohort of people with a history of injecting drugs in Baltimore, Maryland, USA. Participants completed at least two study visits between 2014-2022 and were surveyed at each visit about recent (past 6 months) opioid, stimulant, and other substance use. Sociodemographic, other substance use, and depressive symptoms (measured with CES-D) were lagged one study visit in analysis. Multinomial regression analysis with robust variance was used to determine factors associated with transitions in and out of opioid-stimulant polysubstance use, adjusting for demographic characteristics.
Results:
We analyzed N=9,205 study visits from N=1.452 individuals (median 4.0 visits). The sample is predominantly Black race (76%), male (68%) and nearly one-third (28%) were over the age of 55 years. Across all visits, approximately one-fifth reported sustained opioid-stimulant use, while 8% transitioned in and 7% transitioned out of this use pattern. Following periods of opioid-stimulant use, drug injection was associated with sustained use compared to transitioning to opioid use only (adjusted Relative Risk Ratio (aRRR) =2.79, 95%CI=1.94-4.01) or stimulant use only (aRRR=10.77, 95%CI=7.25-16.00) in analysis adjusted for demographic factors. Depressive symptoms were also associated with sustained opioid-stimulant use compared to opioid only use. (aRRR=2.79, 95%CI=1.94-4.01). Both depression and drug injection were associated with transitions from opioid or stimulant use to combined use.
Conclusion:
Injection drug use and depressive symptoms predicted transitioning into and sustained opioid-stimulant use. These results show potentially actionable intervention targets to reduce harms associated with opioid-stimulant use. |