P-625. Deaths Associated with Laboratory-confirmed COVID-19-associated Hospitalizations, Including In-hospital and Post-discharge Deaths, COVID-NET, March 2020 – September 2023

Abstract Background Deaths from COVID-19 in the US have been tracked using death certificates with COVID-19 listed as a cause of death (COD). However, non-specific CODs or complications of COVID-19, such as myocardial infarction, may be listed as COD for those who died because of COVID-19. We aimed to describe trends in all-cause mortality associated with COVID-19-associated hospitalization and how those deaths are coded on death certificates. Data from the COVID-19-Associated Hospitalization Surveillance Network (COVID-NET) were used to describe in-hospital and post-discharge mortality from March 2020–September 2023.Table.Demographic characteristics of patients with COVID-19-associated hospitalizations, March 2020-September 2023Figure 1.Percentage of patients with COVID-19-associated hospitalizations who died in-hospital or ≤30 days of discharge, by age group and surveillance period,* COVID-NET, March 2020-September 2023. Methods COVID-NET is a population-based surveillance system in 12 states that captures laboratory-confirmed COVID-19-associated hospitalizations of any patient residing in the catchment areas with a positive SARS-CoV-2 test during hospitalization or ≤ 14 days prior to admission. Chart reviews were conducted on a random sample stratified by age, site and month; percentages were weighted to account for the probability of selection. Hospitalizations were linked to death certificates to identify those who died ≤ 30 days of hospital discharge; the proportion with COVID-19 as a COD was described. Logistic regression was used to assess trends.Figure 2.Percentage of COVID-19-associated deaths with COVID-19 listed as cause of death*, including in-hospital deaths and deaths within 30 days of hospital discharge, by surveillance period**, COVID-NET, March 2020-September 2023. Results 482,734 COVID-NET hospitalizations were identified during the study period; 71,729 (14.9%) had chart review. Among these, 12% were in patients who died; 40.9% (95% confidence interval (CI): 38.6%–43.2%) of deaths occurred in October 2020-September 2021 (Table). The proportion of hospitalized patients who died decreased over time in all age groups (p< 0.001) (Figure 1). 65.5% (95% CI: 62.6%–68.3%) of all deaths occurred among those ≥75 years, 44.6% (95% CI: 40.9%–48.4%) of which occurred post-discharge (Figure 1). This group also comprised 77.3% (95% CI: 72.9%–81.3%) of post-discharge deaths. Among in-hospital deaths, the proportion with a COVID-19 COD decreased from 95% (95% CI: 92%–97%) in 2019–2020 to 60% (95% CI: 50%–70%) in 2022–2023 (Figure 2). Conclusion A substantial proportion of COVID-19-associated deaths occurred after discharge, especially in older adults, who accounted for most deaths. Ascertainment based on COVID-19 as a COD may underestimate COVID-19-associated deaths. Disclosures Lucy S. Witt, MD, MPH, Merck & Co: Grant/Research Support Val Tellez Nunez, MPH, Michigan Department of Health and Human Services, CSTE Federal Grant: Grant/Research Support Melissa Sutton, MD, MPH, Centers for Disease Control and Prevention Emerging Infections Program: Grant/Research Support