Secular Trends in Acute Respiratory Distress Syndrome: A 20-Year Analysis of the National Inpatient Sample.

Abstract

Mortality from acute respiratory distress syndrome (ARDS) remains high, but large-scale longitudinal analyses in the pre-COVID era are limited. How has in-hospital mortality changed over time among mechanically ventilated ARDS (MV-ARDS) patients in the United States between 2000 and 2019? We performed a retrospective cohort study using the National Inpatient Sample from 2000 to 2019. Adult, non-elective admissions with a diagnosis of ARDS and concurrent invasive mechanical ventilation were included. The cohort was stratified by ICD coding era (ICD-9: 2000-Q3 2015; ICD-10: Q4 2015-2019). Outcomes included in-hospital mortality, length of stay (LOS), and hospitalization charges. Hospitalization charges were adjusted for Consumer Price Index (CPI) for hospital services to 2019 dollars. Adjusted trend analyses were performed separately for each coding era using logistic and linear regression models. Among 205,393 MV-ARDS admissions (ICD-9: n = 146,888; ICD-10: n = 58,505), mortality declined during the ICD-9 period (OR 0.96 per year, 95% CI 0.95-0.97, p<0.001) but increased during the ICD-10 period (OR 1.05 per year, 95% CI 1.01-1.08, p=0.004). The LOS and hospitalization charges decreased during the ICD-9 era but showed no significant improvement in the ICD-10 period, likely reflecting the rising cost of managing more complex ARDS patients during the ICD-10 period. The ICD-10 cohort had a greater comorbidity burden and were more likely to have a pulmonary etiology for ARDS.