Drivers of Increased Hospital Mortality for Non-COVID-19 Conditions During COVID-19 Surges in 2020

BACKGROUND: The COVID-19 pandemic disrupted health behaviors, health care delivery, and public health systems. We evaluated whether hospital mortality among non-COVID-19 patients increased during COVID-19 surge periods and whether these effects varied across patient subgroups. METHODS: We conducted a retrospective cohort study using administrative claims from the 2020 Arizona, Iowa, Mississippi, and New York State Inpatient Databases and the California Patient Discharge Dataset. The cohort included 3,706,070 hospitalized adults aged 40 years or older without COVID-19. COVID-19 surge periods were defined for each state using the monthly average hospital COVID-19 census. Multilevel logistic regression models with hospital-level random intercepts were used to estimate adjusted odds of in-hospital mortality during surge versus nonsurge periods, adjusting for age, comorbidities, severity of illness, and hospital clustering. Interaction testing evaluated heterogeneity by race, payer, state, and ZIP code-level median household income. RESULTS: Non-COVID-19 patients hospitalized during surge periods experienced higher all-cause in-hospital mortality compared with nonsurge periods (3.6% versus 3.3%) and 10% higher adjusted odds of death (n=6482, adjusted odds ratio: 1.10, 95% CI: 1.08-1.11). Surges disproportionately impacted patients from low-income ZIP codes ( P =0.008). CONCLUSIONS: Hospital mortality among non-COVID-19 patients increased during COVID-19 surges, independent of measured comorbidities and severity of illness, suggesting potential indirect patient safety risks associated with system strain. The greater impact observed among lower-income populations highlights vulnerabilities that may emerge during periods of extreme health care stress.