Functional clinical impairments and frailty in interstitial lung diseases patients

Background Patients with interstitial lung diseases (ILD) often present with persistent dyspnea and reduced exercise capacity and quality of life, but their functional limitation in relation to their frailty status remain unclear. We thus aimed to compare the exercise tolerance, functional mobility and muscle function and composition between ILD participants and healthy subjects and according to their frailty status.

Method A total of 36 ILD participants and 15 heathy subjects performed a six-minute walking test (6MWT), a 1-minute Sit-to-Stand test (1STS), a Short Physical Performance Battery (SPPB) test, a hand grip test and a complete quadriceps function testing. Patient-related impacts were assessed via questionnaires. Muscle composition was obtained using non-contrast computed tomography scans. The frailty status of patients with ILD was determined using the Fried Frailty Phenotype Assessment.

Results In comparison to control subjects, ILD participants exhibited a significantly lower performance in every exercise and functional capacity tests, a higher dyspnea and depression scores and a worse quality of life. In ILD participants, the same observations was noted for frail subgroup in comparison to the robust subgroup. No difference in muscle function and composition was observed between the ILD and control group but mid-thigh muscle cross-sectional area and skeletal muscle index were significantly reduced in frail ILD participants.

Conclusion ILD patients present a reduced exercise tolerance and functional capacity, and have a decreased health-related quality of life when compared to a healthy subjects. Physical frailty seems associated with worse clinical status, exercise tolerance, muscle and functional impairment and decreased quality of life. 1STS may be a good discriminatory test for frailty status in ILD patients.