An interrupted time series analysis of trends in opioid-related emergency department visits from pre-COVID-19 pandemic to pandemic, from the Canadian Hospitals Injury Reporting and Prevention Program

(2023) 23:1483 Yao et al. BMC Public Health https://doi.org/10.1186/s12889-023-16414-z BMC Public Health Open Access RESEARCH An interrupted time series analysis of trends in opioid‑related emergency department visits from pre‑COVID‑19 pandemic to pandemic, from the Canadian Hospitals Injury Reporting and Prevention Program Xiaoquan Yao1*, Steven R. McFaull1, André S. Champagne1 and Wendy Thompson1 Abstract Background Opioid-related emergency department (ED) visits in Canada increased during the COVID-19 pandemic, but how trends in volume and case severity changed from pre-pandemic times through the pandemic is not known. Trends in ED visits related to specific types of opioids also remain unclear. Our objective was to describe pre-pandemic trends and how they changed with the onset of COVID-19 and thereafter. Methods Based on data from the Canadian Hospitals Injury Reporting and Prevention Program, we identified opioidrelated ED visits and constructed a time series from March 12, 2018 through March 7, 2021—two pre-COVID periods and one COVID period. We used an interrupted time series (ITS) analysis to examine trends in volume and case severity. We compared medians and means of monthly counts and percentages of severe cases between the periods, by sex, age, and opioid type. Results Before the pandemic, there was an increasing trend in fentanyl-related visits for males, females and 25to 64-year-olds, and a decreasing trend in heroin-related visits for males and 18- to 64-year-olds. Fentanyl-related visits for 18- to 24-year-olds showed an immediate increase at the start of the pandemic and a decreasing trend during the pandemic. Heroin-related visits for 12- to 17-year-olds had an immediate increase at the start of the pandemic; for 18- to 24-year-olds and 45- to 64-year-olds, the prior decreasing pre-pandemic trend ceased. For pooled opioidrelated visits, no significant trend in the percentage of severe cases was observed throughout the entire study period. Conclusion This study shows that an ITS approach in trend analysis is a valuable supplement to comparisons of before and after measures (with or without controlling seasonal effects). The findings provide evidence on how ED presentations for opioid use evolved in Canada from 2018 to 2021. The results can inform policies designed to reduce opioid-related harm in the context of a public health emergency. Keywords Opioids, COVID-19, Interrupted time series analysis, Emergency department visits, Canadian Hospitals Injury Reporting and Prevention Program (CHIRPP), Fentanyl, Heroin *Correspondence: Xiaoquan Yao Full list of author information is available at the end of the article © Crown 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Yao et al. BMC Public Health (2023) 23:1483 Introduction In Canada, the harms of opioid use increased during the COVID-19 pandemic [1, 2]. At the national level, there was a 91% increase in apparent opioid toxicity deaths and a 24% increase in opioid-related poisoning hospitalizations (Quebec not included) from April 2020 through March 2022, compared with the previous two years (April 2018 through March 2020) [1]. Several American studies have examined trends in opioid-related emergency department (ED) visits before and during the pandemic [3–8]. Canadian studies are scarce, but a table presenting opioid-related ED visits based on data from the National Ambulatory Care Reporting System (partial coverage of Canadian EDs) has been published [2, 9]. According to the table, the volume of opioid-related ED visits for selected months during the pandemic (March 2020 through June 2021), compared with the same months pre-pandemic (January 2019 through December 2019), initially decreased (March through May 2020) and then rose (June 2020 through June 2021). This type of comparison offers one perspective on pre-pandemic and pandemic contrasts, but it is not enough to understand the effect of pre-pandemic trends on the pandemic period and how trends changed with the onset of COVID-19 and thereafter. To our knowledge, no Canadian studies have examined trends in ED visits related to specific types of opioids, such as fentanyl and heroin, before and during the pandemic. Wastewater surveys from five major Canadian cities, reflecting community consumption of opioids, suggested that trends for specific opioids differed: an increase in fentanyl, a decrease in codeine, and no significant change in morphine and methadone [10, 11]. Additionally, fentanyl and its analogues were reported more frequently in apparent opioid-related deaths and poisoning hospitalizations [1]. Trends in ED visits related to specific opioids were not clear. As well, our literature search failed to find studies of trends in the severity of opioid-related ED visits before and during the pandemic. Public health restrictions and fear of contagion would likely affect health care-seeking behaviour, [12] resulting in only the more severe opioid-related cases going to the ED. Thus, we would expect the severity of ED visits to increase at the start of the pandemic. The main objective of this analysis was to use an interrupted time series (ITS) approach [13] to examine trends in opioid-related ED visits from pre-pandemic through pandemic times. We aimed to describe the trend that existed before the pandemic and how it changed with the onset of COVID-19 and thereafter. We analysed trends in both volume and case severity for opioid-related ED visits. The second objective was to conduct sex-, age- and Page 2 of 14 opioid type-specific analyses wherever sufficiently granular data were available. Methods Data source Our study was based on ED visit data from the Canadian Hospitals Injury Reporting and Prevention Program (CHIRPP), an injury and poisoning sentinel surveillance system funded and administered by the Public Health Agency of Canada (PHAC) [14]. CHIRPP, which collects ED visit data, currently operates in 11 pediatric and nine (...truncated)