Ambulance services attendance for mental health and overdose before and during COVID-19: an interrupted time series comparison of regions in Canada and the United Kingdom (Preprint) Journal Articles

Background: The COVID-19 pandemic impacted mental health and healthcare systems globally. This study examined its impact on ambulance attendances for mental health and overdose, comparing similar regions in the United Kingdom (UK) and Canada that implemented different public health measures. Methods: An interrupted time series study using 182,497 ambulance attendance records for mental health and overdose in the UK (East Midlands region) and Canada (Hamilton and Niagara regions) from Jan 1, 2019 to July 31, 2020. Negative binomial regressions modelled the count of attendances per week per 100 000 population prior to the pandemic, at lockdown, and in the weeks following lockdown. Stratified analyses were conducted by sex and age. Results: Ambulance attendances for mental health and overdose had very small week-over-week increases prior to lockdown (e.g., IRR=1.002, 95%CI 1.002-1.003 for mental health [UK]). However, substantial changes were observed at the time of lockdown; while the rate of overdose attendances significantly dropped in the study regions of both countries (IRR=0.573, 95%CI 0.518-0.635 [UK]; IRR=0.743, 95%CI 0.602-0.917 [Canada]), the rate of mental health attendances increased in the UK region only (IRR=1.125, 95%CI 1.031-1.227 [UK]; IRR=0.922, 95%CI 0.794-1.071 [Canada]). Different trends were observed based on sex and age category within and between study regions. Conclusions: The observed changes in ambulance attendances for mental health and overdose at the time of lockdown differed between the UK and Canada study regions. These results may inform future pandemic planning and further research on the public health measures that may explain observed regional differences.