Impact of COVID-19 Pandemic on Emergency Department Visits for Opioid Use Disorder Across University of California Health Centers.

Introduction: Coronavirus 2019 (COVID-19) has had a devastating impact on mental health and access to addiction treatment in the United States, including in California, which resulted in the highest rates of emergency department visits (ED) for opioid poisoning in 2020. As California slowly returns to pre-pandemic normalcy, it remains uncertain whether the rates of opioid-related events have slowed down over time. We hypothesized that the number of opioid-related ED visits were exacerbated after the period of the COVID-19 pandemic and continue at a high rate in the present.

Methods: In this analysis we searched the University of California (UC) Health Data Warehouse-a database of electronic health records from six academic medical centers-for opioid related ED visits, identifiying using the following International Classification of Diseases, 10 Ed, Clinical Modification codes: F11 codes, and T40.0*, T40.1*, T40.2*, T40.3*, T40.4*, T40.6*. Opioid overdose-associated visits were classified by types of opioids involved: heroin (T40.1*); prescription opioids (T40.2* or T40.3*); and synthetic opioids (T40.4*). We performed interrupted time analysis to estimate the immediate (level) change and change-in-time trend (trend change), from before (January 2018-October 2019) and during the pandemic (April 2020-December 2022). Monthly visit rates were evaluated with negative binomial regression adjusted for first-order autoregression and using all-cause ED counts as the offset. We present effect sizes as rate ratios (RR) and 95% confidence intervals (CI), tested at α = .05.

Results: We observed a decrease in overall ED visits from 28,426 to 25,121 visits in December 2019 and June 2021, respectively across all six UC Health Centers. Before COVID-19, we found that ED visit rates steadily increased for all outcomes ( < 0.05) except synthetic opioids. Total opioid-related ED visit rates increased by 15% (RR 1.15, 95% CI 1.02-1.29,  = 0.20) immediately after March 2020 before decreasing by 0.5% every month, albeit without statistical significance (RR .995, 95% CI .991-1.00,  = 0.06). Opioid-related events across the six academic medical centers increase from 232 in December 2019, representing a single month's total, and peaked at 315 in June 2021. Similar trends were observed with prescription opioid overdoses, with a step increase of 44% (RR 1.44, 95% CI 1.10-1.89,  = .008) before plateauing after March 2020 (RR 1.01, 95% CI .998-1.02,  = 0.12). Specifically, the total number of prescription opioid-related ED visits more than doubled between December 2019 (22 visits) and June 2021 (49 visits). After March 2020, ED visit rates for synthetic opioid overdoses were increasing steadily by 4% every month (RR 1.04, 95% CI 1.02-1.06,  = .001), unlike with heroin, which was observed with an 8% monthly reduction (RR .92, 95% CI .90-.93,  < .001). No immediate increase in visit rates was observed for either opioid.

Conclusion: While opioid-related ED admissions among the UC health centers showed an overall decrease, prescription and synthetic opioid overdoses remained significantly higher than pre-pandemic trends as of December 2022. A multilevel approach to improve awareness of new opioid health policies could ameliorate these alarming rises in the post-pandemic era.