BACKGROUND: In March 2020, in response to the COVID-19 emergency, Ontario, Canada implemented public health risk mitigation strategies, including the closures of schools and non-essential businesses, physical distancing, border closures, and modified health services. We examined their association with changes in opioid toxicity mortality and assessed variations across age, sex, health region, and drug type.
METHODS: Opioid toxicity death records (January 2018 to February 2021) from the Ontario Office of the Chief Coroner were analyzed using a generalized linear model for count time series. Our study estimates the changes in the weekly death count following the first (March 17th, 2020, to May 19th, 2020) and second (November 23rd, 2020, to February 10th, 2021) waves of province-wide lockdown measures, modelling interventions as a level shift in the number of opioid toxicity deaths between those dates.
RESULTS: Across the study period, of 5573 individuals who died, 73.7% were male, and the median age was 40 (interquartile range: 31 to 51). The weekly number of deaths ranged from 10 to 72. Following the province-wide state of emergency and first lockdown, there was a step increase in the number of deaths, with an estimated Rate Ratio of 1.20 (95%CI 1.00 to 1.79). There was no significant change following the second wave of lockdown measures (1.06 [95%CI 0.92 to 1.95]).
IMPLICATIONS: The period after initial COVID-19 measures was associated with increases in opioid toxicity mortality. Future responses to public health emergencies must proactively mitigate the potential unintended consequence of competing hazards of mortality among substance-using populations.