Hospitalization Rates in Interstitial Lung Disease: An Analysis of the Pulmonary Fibrosis Foundation Registry

RATIONALE

Little is known about hospitalization in other types of interstitial lung disease (ILD) besides idiopathic pulmonary fibrosis (IPF).

OBJECTIVES

We sought to determine the frequency of hospitalizations in various types of ILD and elucidate the association of hospitalization with outcomes.

METHODS

An analysis of the Pulmonary Fibrosis Foundation Patient Registry data was performed. Inpatient hospitalization rates and survival following hospitalization were compared for various types of ILD.

RESULTS

Hospitalization rates were similar across ILD types (40.6% of IPF participants, 42.8% of connective tissue disease related ILD (CTD-ILD), 44.9% of non-IPF idiopathic interstitial pneumonia (IIPs), 46.5% of chronic hypersensitivity pneumonitis (CHP) participants, and 53.3% of "other" ILD participants). All-cause hospitalization was not associated with decreased transplant-free survival (adjusted hazard ratio (AHR) 1.20, 95% CI: 0.98, 1.46, p=0.0759) after adjusting for co-morbidities and severity of illness; however respiratory-related hospitalization was (AHR 1.53, 95% CI: 1.23, 1.90, p=0.0001). CTD-ILD (HR 0.43, 95% CI: 0.25, 0.75, p=0.0031) and non-IPF IIP (HR 0.3, 95% CI: 0.15, 0.58, p=0.005) had a lower risk of death following hospitalization compared to IPF while CHP (HR 0.67, 95% CI: 0.37, 1.20, p=0.1747) and "other-ILD" (HR 0.54, 95% CI: 0.19, 1.54, p=0.25) had a comparable risk to IPF.

CONCLUSION

Rates of hospitalization are similar across ILD subtypes. The risk of death or transplant following hospitalization is lower in CTD-ILD, CHP and non-IPF IIP compared to IPF participants. In a mixed population of ILD participants, all-cause hospitalizations were not associated with decreased transplant-free survival; however respiratory-related hospitalizations were.