Prognostic value of clinical exercise testing in idiopathic pulmonary fibrosis

Current guidelines for referring patients with idiopathic pulmonary fibrosis (IPF) for lung transplantation, based on resting parameters, are insufficient to predict 3-year mortality. The aim of this study was to determine the prognostic value of cardio-pulmonary exercise testing (CPET) in patients with IPF. A multicentre retrospective study of 3-year outcome was made on 63 adult patients with IPF who underwent CPET with blood gas analysis. Demographic data, resting pulmonary function and CPET parameters were collected to perform a univariate survival analysis. To estimate prognosis at 3 years, a multivariate logistic regression analysis by Kaplan-Meier curves and log-rank tests was performed. Forty-four patients (70%) were alive without lung transplant at the end of the 3-year follow-up: 19 patients (30%) were dead (n = 14) or transplanted (n = 5). Univariate analysis indicated that: at rest lower TLC, FVC, DLCO and PaCO2, higher alveolo-arterial gradient for oxygen [P(A-a)O-2] and pH; at ventilatory threshold (VT) higher VE/VO2 and VE/VCO2 and at peak exercise higher VE/VO2 and VE/VCO2, higher pH and Delta P(A-a)O-2/Delta VO2 (mmHg/L), lower VO2 peak, PaO2 and VO2/FC were associated with a significantly lower survival at 3 years. The multivariate logistic regression analysis showed that CPT (< 65%) and VE/VO2 at VT (> 45) were independently associated with a lower survival at 3 years. Restriction and hyperventilation at ventilatory threshold are major prognostic factors in the course of IPF. CPET with blood gas analysis may have a prognostic value in these patients and initial evaluation of these parameters can help to predict disease progression. (C) 2011 SPLF. Published by Elsevier Masson SAS. All rights reserved.