Background: Frailty in patients with ILD has been attracting attention for its important prognostic marker and an impact on comprehensive approach. However, the diagnosis of frailty requires comprehensive assessment and is not easily implemented in a daily clinical practice.

Objective: To assess the clinical characteristics of frailty and easy predictive tool for frailty in patients with ILD.

Methods: In this cross-sectional study, 130 Japanese patients with ILD were enrolled. Frailty was determined using the Kihon Checklist (KCL). Its associations with clinical parameters including patient-reported outcomes, pulmonary functions, and exercise tolerance were examined.

Results: The frequency of Frailty was 31.3%. There were significant differences in mMRC score, PROMs-D score, 6MWD, 1-min sit-to-stand test (1STST) repetition and %DLco between the Frail and Non-frail groups. Moreover, mMRC score, PROMs-D score, 6MWD and 1STST repetition was effective in stratifying frailty (AUC: 0.882, 0.916, 0.841, 0.864, respectively).

Conclusion: Dypnea scale and 1STST may be useful and simple tools to predict frailty status in patients with ILD.