Association Between Hospital Occupancy Rate and Inpatient Complications During The COVID-19 Pandemic

Introduction: The COVID-19 pandemic strained the U.S. healthcare system due to significant requirements for inpatient and intensive care unit resources for COVID-19 patients. We examined the association between hospital occupancy and incidence of complications during the COVID-19 pandemic in the Military Health System. Materials and Methods: This retrospective cross-sectional study used inpatient hospital encounters data (October 2019-May 2023) from the U.S. Military Health System Data Repository. TRICARE beneficiaries admitted and treated for traumatic injury, emergency general surgery conditions, myocardial infarction, or cerebrovascular accident at a military treatment facility. We used multivariable logistic regression to determine if the incidence of complications (i.e., catheter-acquired urinary tract infections, central line acquired bloodstream infections, decubitus ulcers, deep vein thrombosis, pulmonary embolism) was associated with changes in hospital occupancy rate (i.e., inpatient days per bed-day per month). Results: Of 24,926 TRICARE beneficiaries eligible for inclusion, 58% were male, 55% White, and 84% non-Hispanic. The average hospital occupancy rate was 0.45 inpatient days per bed-day per month (SD = 0.24) for included hospitals from October 2019 to May 2023. Compared to the lowest hospital occupancy tertile, the likelihood of complications was 36% higher at hospitals in the middle tertile (OR: 1.36, 95% CI, 1.15-1.61), and 20% at hospitals in the higher tertile (OR: 1.20, 95% CI, 1.01-1.43). Conclusions: The incidence of inpatient complications appeared to increase with increasing hospital occupancy. Future disaster preparedness efforts should proactively address widespread workforce shortages to mitigate the effects of hospital occupancy surges.