Long-term prognostic impact of clinical frailty scale on acute exacerbation of fibrotic interstitial lung disease: a retrospective cohort study

Acute exacerbations (AE) of fibrotic interstitial lung disease (fILD) are associated with a poor prognosis; however, the factors that predict long-term outcomes remain unclear. This study aimed to evaluate whether pre-admission frailty, as assessed using the Clinical Frailty Scale (CFS), predicts 1-year mortality and other relevant outcomes in patients with AE-fILD. This single-centre retrospective study included 125 patients hospitalised for AE-fILD between January 2017 and September 2023. Patients were categorised into low (score: 1–4) and high (score: 5–9) CFS groups based on their CFS scores. The primary outcome was 1-year mortality, and the secondary outcomes included in-hospital mortality, 90-day mortality, and home discharge. Prognostic associations were evaluated using Kaplan–Meier and multivariable Cox regression analyses, adjusted for age, lactate dehydrogenase levels, SpO₂/FIO₂ ratio, and home oxygen therapy. The median patient age was 78 years, and 41.6% of patients were included in the high CFS group. Kaplan–Meier analysis revealed a significantly lower 1-year survival in the high-CFS group (log-rank, p < 0.001). After adjustment, a high CFS score remained independently associated with increased 1-year mortality (adjusted hazard ratio, 2.20; 95% confidence interval, 1.31–3.68; p = 0.003). Higher in-hospital and 90-day mortality rates and lower home discharge rates were observed in the frail subgroup. Preadmission frailty, as assessed using the CFS, independently predicts 1-year mortality and is associated with adverse outcomes in patients with AE-fILD. Incorporating a CFS-based frailty assessment may provide a simple and useful prognostic tool to inform clinical decision-making and promote patient-centred care. An independent ethics committee approved the study (Institutional Review Board of the Kobe City Medical Center General Hospital [number zn241009 date October 8, 2024]), which was performed in accordance with the Declaration of Helsinki and Guidelines for Good Clinical Practice.