The relationship between COVID-19 and opioid-related emergency department visits in Alberta, Canada: an interrupted time series analysis

Emergency departments (EDs) are important health care access points for people who use drugs (PWUD), but little is known about whether the onset of the COVID-19 pandemic was associated with changes in opioid-related emergency presentations. We investigated whether (1) the onset of the COVID-19 pandemic was associated with any change in average rates of opioid-related ED visits in Alberta; and (2) this varied across regions with different COVID-19 case rates. We conducted maximum-likelihood interrupted time series analyses to compare opioid-related ED visits during the "prepandemic period" (3 March 2019-1 March 2020) and the "pandemic period" (2 March 2020-14 March 2021). There were 8883 and 11 657 opioid-related ED visits during the prepandemic and pandemic periods, respectively. The onset of the COVID-19 pandemic was associated with an increase in opioid-related ED visits (Edmonton: IRR = 1.37, 95% CI: 1.30- 1.44, p < 0.05; Calgary: IRR = 1.14, 95% CI: 1.07-1.20, p < 0.05; Other health zones: IRR = 1.14, 95% CI: 1.07-1.21, p < 0.05). Changing COVID-19 case counts did not correspond with changing rates of opioid-related ED visits across regions. The increase in opioid-related ED visits associated with the onset of the COVID-19 pandemic was unrelated to COVID-19 case prevalence in Alberta.