Factors associated with non-intervention of antifibrotic agents in IPF patients

The efficacy of antifibrotic agents in idiopathic pulmonary fibrosis (IPF) has been demonstrated and early introduction is recommended, especially in patients with preserved performance status (PS). We aimed to determine the proportion of untreated IPF cases using real-world data and to assess the factors associated with non-intervention. A prospective observational study using questionnaires was performed on 518 patients with interstitial lung disease (ILD) and their attending physicians who visited a clinic, general hospital, or tertiary respiratory center between December 2019 and October 2020. Patients responded with subjective symptoms and PS, whereas physicians responded with diagnosis, treatment, and reasons for their treatment choices. Principal component analysis (PCA) was performed using age, sex, BMI, medical facility, specialized tests, and symptom severity. We included 207 patients with IPF. Among them, 168 has a good PS (≤2), which could be indicative of treatment; 130 (77.4%) were not treated with antifibrotic agents. The PCA revealed a trend consistent with that of antifibrotic agent therapy and the distribution of medical facilities, with a treatment intervention rate of 16% in general hospitals and 62% in tertiary respiratory centers. In general hospitals, low symptom severity (PS, mMRC, and no use of long-term oxygen therapy) was a relevant factor for non-intervention with antifibrotic agents (p