The Clinical Frailty Scale for Risk Stratification in Patients With Fibrotic Interstitial Lung Disease

Abstract

Background: Previous studies have shown the importance of frailty in patients with fibrotic interstitial lung disease (ILD).

Research question: Is the Clinical Frailty Scale (CFS) a valid tool to improve risk stratification in patients with fibrotic ILD?

Study design and methods: Patients with fibrotic ILD were included from the prospective multicenter Canadian Registry for Pulmonary Fibrosis. The CFS was assessed using available information from initial ILD clinic visits. Patients were stratified into fit (CFS score 1-3), vulnerable (CFS score 4), and frail (CFS score 5-9) subgroups. Cox proportional hazards and logistic regression models with mixed effects were used to estimate time to death or lung transplantation. A derivation and validation cohort was used to establish prognostic performance. Trajectories of functional tests were compared using joint models.

Results: Of the 1,587 patients with fibrotic ILD, 858 (54%) were fit, 400 (25%) were vulnerable, and 329 (21%) were frail. Frailty was a risk factor for early mortality (hazard ratio, 5.58; 95% CI, 3.64-5.76, P < .001) in the entire cohort, in individual ILD diagnoses, and after adjustment for potential confounders. Adding frailty to established risk prediction parameters improved the prognostic performance in derivation and validation cohorts. Patients in the frail subgroup had larger annual declines in FVC % predicted than patients in the fit subgroup (-2.32; 95% CI, -3.39 to -1.17 vs -1.55; 95% CI, -2.04 to -1.15, respectively; P = .02).

Interpretation: The simple and practical CFS is associated with pulmonary and physical function decline in patients with fibrotic ILD and provides additional prognostic accuracy in clinical practice.

Keywords: aging; disease progression; frailty; idiopathic pulmonary fibrosis; interstitial lung disease; survival.