LAUSR

Study Obectives: The coronavirus disease 2019 pandemic has resulted in decreased ED volumes across the country. Our objective was to better characterize how the impact of COVID-19 prevalence in the community affected public utilization of ED resources for non-COVID-19 encounters during the pandemic. Methods: This was a retrospective cross-sectional study performed at a single urban quaternary care academic medical center with 95,000 annual visits in Los Angeles County (LAC). Weekly ED COVID-19 and non-COVID-19 (NC) volumes were abstracted from May 2, 2019 through April 24, 2021;other data parameters obtained included age (<18, 18-64, 65+), arrival mode (walk-in, ambulance), Emergency Severity Index (ESI), and ED disposition (discharge, admit/transfer, psych transfer, death). COVID-19 encounters were queried by any ED diagnosis of “COVID” or “coronavirus.” SARS-CoV-2 testing and vaccination data were obtained from LAC from March 10, 2020 through May 1, 2021. We calculated LAC SARS-CoV-2 testing positivity rates and cumulative vaccination rates per week and examined daily ED NC volumes in relation to LAC testing positivity rates and vaccination rates. Paired t-tests were conducted to compare ED NC volumes before and after the start of the pandemic. Pearson correlation coefficients were used to compare ED NC volumes to LAC testing positivity and vaccination rates. Results: ED NC volumes reduced by an average of 29% one year prior to and after March 2020 when the COVID-19 pandemic began;there was a significant difference in volume before (M=1803, SD 53) and after (M=1284, SD 214), t(51)=2.01, P=<.001. The week of April 3 had the largest relative volume decrease of 61% with state of emergency and stay-at-home orders issued in the preceding two weeks. NC volumes regained pre-pandemic levels by the week of April 10, 2021 and sustained through May 2021. On April 10, 2021 47% of the eligible population age 16 and over in LAC had received at least 1 COVID-19 vaccination dose. Figure 1 represents trend lines of ED NC volume over time in relation to LAC COVID test positivity rate and vaccination percentage. The age breakdown showed pediatric <18 NC volumes had the highest relative reduction, but this volume only accounted for 5% of ED NC visits in our study period. Age groups 18-64 and 65+ had NC relative reductions of 20% and 22% respectively. The ESI levels 1-5 breakdown showed similar distributions pre and post pandemic;ESI-4 had the largest relative decrease of 37% with ESI-2 and ESI-3 decreasing by 27% and 15% respectively. The arrival method of patients was largely unchanged with walk-ins accounting for 80% and 79% pre and post pandemic. ED NC admission rates increased from 38% to 43% with corresponding decrease in discharges;psychiatric transfers and deaths were unchanged. ED NC volume and LAC COVID test positivity rates were found to have a very strong negative correlation (r(113) = -0.88, p<.001). Conversely ED NC volumes and cumulative LAC 16+ vaccination rates had a very strong positive correlation (r(113) = 0.94, p<.001). Conclusions: The higher the prevalence of COVID-19 in the community, the more hesitant patients behaved in seeking ED care for non-COVID-19 reasons. Lower disease prevalence and increasing vaccination rates correlate with a return of NC volumes back to pre-pandemic levels. [Formula presented]