Hospital Catchment Areas Characteristics and Geographic Regions Associated With Higher COVID-19 Veterans Health Administration Hospitalization During the Omicron Surge

Context: Surges in the ongoing coronavirus-19 (COVID-19) pandemic and accompanying increases in hospitalizations continue to strain hospital systems. Identifying hospital-level characteristics associated with COVID-19 hospitalization rates and clusters of hospitalization "hot spots" can help with hospital system planning and resource allocation.

Objective: To identify (1) hospital catchment area-level characteristics associated with higher COVID-19 hospitalization rates and (2) geographic regions with high and low COVID-19 hospitalization rates across catchment areas during COVID-19 Omicron surge (December 20, 2021-April 3, 2022).

Design: This observational study used Veterans Health Administration (VHA), US Health Resource & Services Administration's Area Health Resources File, and US Census data. We used multivariate regression to identified hospital catchment area-level characteristics associated with COVID-19 hospitalization rates. We used ESRI ArcMap's Getis-Ord Gi* statistic to identify catchment area clusters of hospitalization hot and cold spots.

Setting and participants: VHA hospital catchment areas in the United States (n = 143).

Main outcome measures: Hospitalization rate.

Results: Greater COVID-19 hospitalization was associated with serving more high hospitalization risk patients (34.2 hospitalizations/10 000 patients per 10-percentage point increase in high hospitalization risk patients; 95% confidence intervals [CI]: 29.4, 39.0), fewer patients new to VHA during the pandemic (-3.9, 95% CI: -6.2, -1.6), and fewer COVID vaccine-boosted patients (-5.2; 95% CI: -7.9, -2.5).We identified 2 hospitalization cold spots located in the Pacific Northwest and in the Great Lakes regions, and 2 hot spots in the Great Plains and Southeastern US regions.

Conclusions: Within VHA's nationally integrated health care system, catchment areas serving a larger high hospitalization risk patient population were associated with more Omicron-related hospitalizations, while serving more patients fully vaccinated and boosted for COVID-19 and new VHA users were associated with lower hospitalization. Hospital and health care system efforts to vaccinate patients, particularly high-risk patients, can potentially safeguard against pandemic surges.Hospitalization hot spots within VHA include states with a high burden of chronic disease in the Great Plains and Southeastern United States.