Concurrent opioid and stimulant use and fatal overdose among a general population sample in British Columbia, Canada: A cohort study

Stimulant use has been rising among people with opioid use disorder in recent years in North America, alongside a parallel rise in illicit drug toxicity (overdose) deaths. This study aimed to examine the association between opioid and/or stimulant use and fatal overdose.

Data from a universal health insurance client roster were used to identify a 20% random general population sample (aged ≥12) in British Columbia, Canada between January 1 2015 and December 31 2018 (N=1,089,682). Provincial health records were used to identify people who used opioids and/or stimulants. Fatal overdose observed during follow-up (January 1 2015- December 31 2018) was retrieved from vital statistics death records and coroners data. Potential confounders including age, sex, health region, comorbidities and prescribed medications were retrieved from the provincial health records.

We identified 7,460 people who used stimulants and or opioids. During follow-up there were 272 fatal overdose events. People who used stimulants had a similar hazard of fatal overdose compared to people who used opioids (HR: , 95% CI:, p). People who used both opioids and stimulants had more than twice the hazard of fatal overdose (HR: 2.02, 95% CI: 1.47-2.78, p<0.001) compared to people who used opioids only. The hazard of death increased over time among people who used both opioids and stimulants.

The findings from this analysis highlight the need to increase services and programs for people who use stimulants and people who use both stimulants and opioids. More research is needed to understand the factors contributing to increased risk of overdose among polysubstance users and people who use stimulants.