Assessment of clinical characteristics and mortality in patients hospitalized with SARS-CoV-2 from January 2022 to November 2022, when Omicron variants were predominant in the United States

To describe the demographic/clinical characteristics, treatment patterns, and mortality among patients hospitalized with COVID-19 during Omicron predominance by immunocompromised and high-risk status. Retrospective observational study of patients hospitalized with COVID-19 between January 1, 2022 and November 30, 2022, using data from the Optum de-identified Clinformatics Data Mart Database. Patient demographic/clinical characteristics, treatments, mortality and costs, were assessed, during the emergence of BA.1 BA.4, BA.5, BA.2.12.1, BA.2.75, BQ.1, XBB Omicron viral subvariants. Overall, 43,123 patients were included, with a mean (standard deviation [SD]) age of 75.5 (12.4) years, 51.8% were female. Immunocompromised patients accounted for 36% of hospitalized patients while only 5.8% received any outpatient COVID-19 treatment within 30 days of hospital admission. The mean (SD) hospital length of stay was 7.9 (7.5) days with 15.5% mortality within 30 days of admission. Mean (SD) hospital costs were $33,975 ($26,392), and 30-day all-cause readmission was 15.1%. Patients with immunocompromised status and those with a higher number of high-risk conditions proceeded to have an elevated proportion of hospital readmissions and mortality within 30 days. Moreover, a higher proportion of mortality was observed during the BA.1 period (20.1%) relative to other variant periods (11.0%). COVID-19 imposed a large healthcare burden, particularly among immunocompromised patients and those with underlying high-risk conditions during Omicron period. Low utilization of outpatient COVID-19 treatments was observed in these high-risk populations eligible for treatment. Continued surveillance and research regarding COVID-19 variants and the impact of outpatient treatment options on high-risk patients is crucial to inform and guide public health action.