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 1-3), vulnerable (CFS 4), and frail (CFS 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 were used to establish prognostic performance. Trajectories of functional tests were compared using joint models.

Results

Of the 1587 patients with fibrotic ILD, 858 (54%) were fit, 400 (25%) vulnerable and 329 (21%) frail. Frailty was a risk factor for early mortality (HR 5.58, 95%CI 3.64-5.76, p<0.001) 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. Frail patients had larger annual declines in forced vital capacity (FVC) %-predicted compared to fit patients (-2.32 (95%CI -3.39 to -1.17) vs. -1.55 (95%CI -2.04 to -1.15); p=0.02, respectively).

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.