Trends in opioid toxicities among people with and without opioid use disorder and the impact of the COVID-19 pandemic in Ontario, Canada: A population-based analysis.

ABSTRACT

BACKGROUND: Across Canada, the COVID-19 pandemic occurred amidst an ongoing drug toxicity crisis. Although elevated rates of substance-related harms have been observed nationally, it remains unknown if the pandemic state of emergency led to disproportionate increases in opioid toxicities among people with opioid use disorder (OUD) compared to those without. METHODS: We conducted a population-based repeated cross-sectional time series analysis of fatal and non-fatal opioid toxicities between January 1, 2014, and December 31, 2021, in Ontario, Canada. We used interventional autoregressive integrated moving average models to examine the impact of the pandemic on monthly rates of opioid toxicities per 100,000 Ontario residents stratified by people with and without OUD. RESULTS: We identified 80,296 opioid toxicities of which 53.5 % occurred among people with OUD. Among 52,052 unique individuals, 60.5 % were male and 46.2 % were 25-44 years old. Between January 2014 and December 2021, the rate of opioid toxicities increased from 2.6 to 10.5 per 100,000 (rate ratio [RR]=4.07). The magnitude of this increase differed among people with OUD (0.8 to 7.4 per 100,000; RR=9.35) and without OUD (1.8 to 3.1 per 100,000; RR=1.74). We observed a significant ramp increase in the overall rate of opioid toxicities following the declaration of the pandemic emergency in March 2020 (+0.19 per 100,000 monthly, 95 % CI 0.029, 0.36, p = 0.021). In a stratified analysis, we found a similar ramp increase among people with OUD (+0.19 per 100,000 monthly, 95 % CI 0.10, 0.28, p < 0.001); however, this was not observed among people without OUD (p = 0.95). CONCLUSIONS: The rate of opioid toxicities accelerated across Ontario following the pandemic-related state of emergency, with the majority of this increase among people with OUD. The important differences observed among people with OUD compared with those without, highlights the critical need for improved access to harm reduction and treatment interventions among this population.