Characteristics of patients with chronic idiopathic interstitial pneumonia undergoing repeated respiratory-related hospitalizations: A retrospective cohort study

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease. Chronic idiopathic interstitial pneumonia (c-IIP) is a group of lung diseases consisting mainly of fibrotic IIPs, and IPF is a type of c-IIP. Some patients with c-IIP undergo respiratory-related hospitalizations (RHs). With the hypothesis that the characteristics of patients who undergo RHs are related to the number of hospitalizations, we reviewed and investigated the RHs of patients with c-IIP. METHODS: We retrospectively examined the data of patients with c-IIP who were admitted to Kindai University Hospital between January 2008 and December 2018 for respiratory-related causes. RESULTS: During the study period, 243 patients with c-IIP were hospitalized a total of 544 times because of respiratory-related causes. The most common reasons for the first RH were acute exacerbation (48.1%) followed by pulmonary infection (32.5%). The most frequent reason for subsequent RHs was pulmonary infection. The in-hospital and 90-day mortality rate of patients with pulmonary infection increased with increasing numbers of RHs. Patients with multiple RHs had significantly worse long-term survival than patients hospitalized a single time. CONCLUSIONS: Pulmonary infection was the most frequent reason for repeated RHs. The proportion of all patients hospitalized for pulmonary infection at each RH increased with increasing numbers of RHs, along with the mortality rate of patients with pulmonary infections. Furthermore, repeated RHs were associated with poor survival.