Clinical outcomes and costs associated with viral lower respiratory tract disease hospitalisations

An updated comprehensive assessment of the burden of hospitalised viral lower respiratory tract disease (LRTD) is especially salient after the COVID-19 pandemic. Therefore, we aimed to comprehensively describe clinical characteristics and outcomes of US adults hospitalised with viral LRTD between 2015 and 2023.

In this retrospective analysis, adults hospitalised between 1 January 2015 and 31 March 2023 were identified using Optum's deidentified Clinformatics Data Mart Database. Index date was the first International Classification of Diseases, 9th/10th Revision (ICD-9/10) code for viral LRTD hospitalisation. Outcomes included intensive care unit (ICU) admission, non-invasive ventilation (NIV), invasive mechanical ventilation/extracorporeal membrane oxygenation (IMV/ECMO), costs, 30-day mortality and 30-day readmissions. Outcomes were stratified by viral aetiology (ICD-9/10), clinical severity and time period (2015-2019; 2020-2021; 2022-2023). Time-to-event data were assessed using Kaplan-Meier estimates.

Of 387 449 patients hospitalised for viral LRTD, 38.1% were admitted to ICU within 30 days of index (84.6% of these were admitted on index date); 8.4% and 8.7%, respectively, received NIV and IMV/ECMO within 30 days of index and 30-day mortality was 15.1%. Median (IQR) length of stay and mean (SD) hospitalisation costs were 7 (4-15) days and $42 752 ($44 841), respectively. Admission to ICU, mortality and costs were substantial across all aetiologies but peaked from 2020 to 2021; readmissions and costs remained high even into 2022-2023.

Severe viral LRTD incurred substantial burden for US healthcare systems across all viral aetiologies, even in non-pandemic years, with frequent ICU admission and ventilation use, and with considerable associated costs. Readmission rates and costs remain high even after the peak of COVID-19.