COVID-19 Hospitalization and 30-Day Readmission: A Cohort Study of U.S. Hospitals

ABSTRACT

Background. Evidence on outcomes after COVID-19 hospitalization is limited. This study aimed to characterize 30-day readmission beyond the initial COVID-19 hospitalization. Methods. This descriptive retrospective cohort study included adult patients admitted between 07/01/2020 and 01/31/2021 with a discharge diagnosis of COVID-19 (ICD-10-CM U07.1), using a large hospital inpatient chargemaster with a linked open claims dataset. The first COVID-19 hospitalization was considered index hospitalization;baseline was defined as first 2 days of index hospitalization;readmission was assessed within 30 days of discharge from index hospitalization. We describe the demographics, treatments and outcomes of the index hospitalization and readmission. Results. For index hospitalization, we identified 111,624 COVID-19 patients from 327 hospitals across US. Mean age was 63 and 54% were male. Over the study period, use of remdesivir (RDV) increased from 11% to 50% while use of steroids (66% -73%) and anticoagulants (32% - 35%) remained relatively stable (Figure 1). Overall, 21% required ICU or CCU admission, 13% died, and median length of stay (LOS) was 7 days (range 4 -11 days). Among 61,182 (55%) with ≥ 30-day follow-up post discharge, all-cause 30-day readmission was 16% and remained stable (15% - 17%) over the study period;median days to readmission was 6 days (range 1-30). All-cause readmission (13 % vs 17%) was lower in patients treated with RDV during index hospitalization over time (Figure 2), particularly in those requiring high flow oxygen (17% vs 18%), low flow oxygen (13% vs 16%) or no oxygen (12% vs 17%), but not in ECMO or invasive ventilation (33% vs 29%). Compared to non-readmitted, readmitted patients were older (60 vs 65), had more comorbidities such as COPD (24% vs 37%) (see Table 1) and LOS (6 vs 7 days) in index hospitalization. Overall, the most frequent diagnoses of readmission were COVID-19 (63%), other viral pneumonia (36%), and acute respiratory failure with hypoxia (34%). Conclusion. In a large, geographically diverse cohort of hospitalized COVID-19 patients, 16% required readmission, especially in those with greater age and comorbidities. Over the study period, all-cause readmission remained stable and was lower in RDV treated patients.