COVID-19 Admission Rates and Changes in US Hospital Inpatient and Intensive Care Unit Occupancy

Abstract

ImportanceThe COVID-19 pandemic had unprecedented effects on hospital occupancy, with consequences for hospital operations and patient care. Previous studies of occupancy during COVID-19 have been limited to small samples of hospitals.ObjectiveTo measure the association between COVID-19 admission rates and hospital occupancy in different US areas and at different time periods during 2020.Design, Setting, and ParticipantsThis cross-sectional study used data from the Healthcare Cost and Utilization Project State Inpatient Databases (2019-2020) for patients in nonfederal acute care hospitals in 45 US states, including the District of Columbia. Data analysis was performed between September 1, 2022, and April 30, 2023.ExposuresEach hospital and week in 2020 was categorized based on the number of COVID-19 admissions per 100 beds (<1 [low], 1-4.9, 5-9.9, 10-14.9, or ≥15 [high]).Main Outcomes and MeasuresThe main outcomes were inpatient and intensive care unit (ICU) occupancy. We used regression analysis to estimate the average change in occupancy for each hospital-week in 2020 relative to the same hospital week in 2019.ResultsThis study included 3960 hospitals and 54 355 916 admissions. Of the admissions in the 40 states used for race and ethnicity analyses, 15.7% were for Black patients, 12.9% were for Hispanic patients, 62.5% were for White patients, and 7.2% were for patients of other race or ethnicity; 1.7% of patients were missing these data. Weekly COVID-19 admission rates in 2020 were less than 4 per 100 beds for 63.9% of hospital-weeks and at least 10 in only 15.9% of hospital-weeks. Inpatient occupancy decreased by 12.7% (95% CI, 12.1% to 13.4%) during weeks with low COVID-19 admission rates and increased by 7.9% (95% CI, 6.8% to 9.0%) during weeks with high COVID-19 admission rates. Intensive care unit occupancy rates increased by 67.8% (95% CI, 60.5% to 75.3%) during weeks with high COVID-19 admissions. Increases in ICU occupancy were greatest when weighted to reflect the experience of Hispanic patients. Changes in occupancy were most pronounced early in the pandemic. During weeks with high COVID-19 admissions, occupancy decreased for many service lines, with occupancy by surgical patients declining by 43.1% (95% CI, 38.6% to 47.2%) early in the pandemic.Conclusions and RelevanceIn this cross-sectional study of US hospital discharges in 45 states in 2020, hospital occupancy decreased during weeks with low COVID-19 admissions and increased during weeks with high COVID-19 admissions, with the largest changes occurring early in the pandemic. These findings suggest that surges in COVID-19 strained ICUs and were associated with large decreases in the number of surgical patients. These occupancy fluctuations may have affected quality of care and hospital finances.

COVID-19 Admission Rates and Changes in Care Quality in US Hospitals

“…In previous work, our group showed that COVID-19 admissions were associated with fluctuations in occupancy. 4 Specifically, the previous study estimated that hospital-weeks in 2020 with low COVID-19 admission rates were associated with a 12.7% reduction in inpatient occupancy and a 5.4% reduction in intensive care unit (ICU) occupancy compared with the same hospital-weeks in 2019. In contrast, hospital-weeks with high COVID-19 admission rates were associated with a 7.9% increase in inpatient occupancy and a 67.8% increase in ICU occupancy.…”

“…Our group’s prior study also provides detail on the distribution of COVID-19 admission rates over time, states, and types of hospitals. 4 …”

“…COVID-19 admissions were identified using International Classification of Diseases, Tenth Revision, Clinical Modification codes U07.1 and J12.82 for patients aged 1 year or older. Following the prior study, 4 we used 5 indicators for the weekly COVID-19 admission rate per 100 hospital beds to allow a nonlinear relationship with outcomes: less than 1 (low), 1 to 4.9, 5 to 9.9, 10 to 14.9, and 15 or greater (high).…”

“… 37 , 38 As the COVID-19 admission rate is a hospital-week–level variable, we followed our prior study and clustered standard errors at the hospital level in all regressions. 4 …”

“… 1 , 2 , 3 However, hospitals often experienced few or no COVID-19 admissions, and during these periods occupancy levels were lower than in 2019. 4 Tracking how patient outcomes changed in response to COVID-19 admissions and occupancy fluctuations may offer insight into the association between hospital strain and care quality.…”