Interstitial lung disease hospitalizations, outcomes, and costs in the United States from 2008 to 2018

Background Interstitial lung diseases (ILD) are associated with frequent hospitalizations, however, limited studies have evaluated the hospitalization rates and outcomes. Study design and methods We extracted hospitalization data for ILD patients using the National Inpatient Sample Database. Regression models were used to assess trends in hospitalizations and outcomes. Results There were 345,063 hospitalizations with a principal diagnosis of ILD from 2008 to 2018. Hospitalization rates were higher in females, older age groups, and those living in rural areas. Rates were lower in those with income levels at or above the median and in the western U.S. Of those hospitalized, 5.1 % died, and ∼37 % required skilled nursing facility/home health. Deaths were lower among females and in those with Medicaid and private insurance. Rates were higher in the older age groups, those with median and above income levels, and those living in medium/small metro and rural areas. The overall hospitalization rate decreased by ∼23 % during this period. The percentage of deaths remained stable (except in rural hospitals) during this period. The average length of stay (LOS) was 5.5 days. The average hospital cost was $10,438 which increased by ∼38 %. Interpretation Hospitalizations for ILD have been decreasing, however, the death percentage has been stable. The LOS has remained stable, but hospital costs have been increasing. We identified differences in ILD hospitalization rates and outcomes/costs based on patient and hospital characteristics. Identifying the causes for these differences would be important in reducing health disparities in ILD patients. Clinical trial registration n/a.