Combined Assessment of Frailty and Respiratory Function in Idiopathic Pulmonary Fibrosis: A Prospective Cohort Study

Background: Idiopathic pulmonary fibrosis (IPF) predominantly affects older adults. Frailty is increasingly recognized as an important feature of IPF, although its prognostic value remains uncertain. This study aimed to assess the prevalence of frailty and concordance among validated instruments, characterize the principal domains of vulnerability identified through comprehensive geriatric assessment (CGA), and evaluate the prognostic value of integrating frailty with indices of respiratory disease severity in older adults with IPF. Methods: We conducted a prospective, single-center study of patients aged 65 years or older with confirmed IPF. Frailty was assessed using the Fried frailty phenotype (FFP), a CGA-derived Frailty Index (CGA-FI), and the Clinical Frailty Scale (CFS). The primary outcome was a composite of all-cause mortality or acute exacerbation during follow-up. Cox proportional hazards models and bootstrap-derived concordance indices were used to evaluate prognostic associations and model discrimination. Results: Among the 140 patients included, the prevalence of frailty ranged from 16.4% according to the CGA-FI to 22.3% according to the FFP, whereas 19.3% were classified as frail according to the CFS. During a median follow-up of 465 days (IQR, 221-1076 days), 35 patients (25.0%) experienced the composite outcome. Frailty assessed using the CFS (CFS ≥5: HR, 3.94; 95%CI, 1.81-8.58) and a higher Gender-Age-Physiology (GAP) stage (GAP II-III: HR, 3.11; 95%CI, 1.39-7.00) were independently associated with the composite outcome. The integrated GAP-CFS model showed good discrimination, with a bootstrap-derived Harrell C index of 0.72 (95%CI, 0.62-0.81). Patients who experienced events also had higher Strength, Assistance in Walking, Rising From a Chair, Climbing Stairs, and Falls (SARC-F) scores and greater functional impairment. Conclusions: Frailty is common and clinically relevant in IPF. Integrating frailty measures with pulmonary indices improves prognostic stratification and supports the use of the CFS and CGA to guide personalized, multidimensional care.