In-Hospital Mortality Among Hospitalized COVID-19 Patients in the United States: How Did It Change in 2022 and 2023?

OBJECTIVES: We previously reported an increase in in-hospital mortality between August-October 2021 among patients hospitalized with coronavirus disease 2019 (COVID-19), with the widespread of severe acute respiratory syndrome coronavirus 2 delta variant. This study aimed to assess potential changes in in-hospital mortality among COVID-19 inpatients in the United States (US) from 01/01/2022 to 09/30/2023 after most countries lifted restrictions due to pandemic.

METHODS: A retrospective cross-sectional study was performed for hospitalized adult patients discharged from 824 geographically diverse US hospitals in the PINC AI Healthcare Database with a principal/secondary diagnosis of COVID-19 (ICD-10-CM code: U07.1) during study period.

RESULTS: Among 651,287 eligible patients with a principal/secondary diagnosis of COVID-19, average age was 66 years, 48.2% were men, 70.7%% were white, 15.8% were black, and 12.3% were Hispanic. Average monthly number of hospitalized COVID-19 patients dropped from 41,700 to 16,766 and in-hospital mortality dropped from 7.3% to 5.0% overall from 2022 to 2023. In-hospital mortality was higher in winter months than in summer months in both years. Patients were older (mean age 70 vs. 65 years) with a higher prevalence of baseline comorbidities (mean Charlson-Deyo Comorbidity Index score 2.8 vs. 2.5) in 2023 than patients in 2022 (both p<0.01). The highest in-hospital mortality was observed in February 2022 (11.5%), which was lower than the peak in 2021 (14.9%). In a subset of patients hospitalized with a principal diagnosis of COVID-19 (n=262,422), in-hospital mortality was the highest in February-March of 2022 (12.2-12.5%). However, it was low in most other months ranging between 3-6% and fell to 2-3% in summer months (June-July).

CONCLUSIONS: Although the in-hospital mortality among COVID-19 inpatients remained high in February 2022, it decreased substantially from 2022 to 2023 despite older and sicker patients in 2023. Patients hospitalized in winter months experienced higher in-hospital mortality than those in summer months.