A simple assessment of dyspnoea as a prognostic indicator in idiopathic pulmonary fibrosis

Abstract

The prognosis in idiopathic pulmonary fibrosis (IPF) is poor. No therapy has been shown to prolong survival. The objective of this study was to examine the prognostic significance of dyspnoea in daily living at baseline in IPF using a simple assessment tool. 93 consecutive patients with IPF, who had undergone evaluation at diagnosis, were included. The level of dyspnoea was assessed using the modified Medical Research Council (MRC) scale. The relationship between data at baseline and survival was examined. A univariate Cox proportional-hazard model showed that forced vital capacity % predicted (hazard ratio (HR) 0.965, 95% CI 0.948-0.982; p<0.0001), diffusing capacity of the lung for carbon monoxide % predicted (HR 0.978, 95% CI 0.963-0.993; p = 0.0041), baseline arterial oxygen tension (HR 0.963, 95% CI 0.938-0.989; p = 0.0060) and modified MRC score (HR 2.402, 95% CI 1.495-3.858; p = 0.0003) were significantly predictive of survival. All variables of the 6-min walk test, including walk distance (HR 0.995, 95% CI 0.992-0.998; p = 0.0020), the lowest arterial oxygen saturation measured by pulse oximetry (S(p,O(2))) (HR 0.944, 95% CI 0.918-0.972; p<0.0001) and the Borg scale (HR 1.285, 95% CI 1.091-1.514; p = 0.0027), were also significant. With stepwise, multivariate Cox proportional analysis, the modified MRC score (HR 2.181, 95% CI 1.333-3.568; p = 0.0019) and the lowest S(p,O(2)) during the 6-min walk test (HR 0.952, 95% CI 0.924-0.981; p = 0.0014) were the most significant. Dyspnoea in daily living, assessed with the modified MRC scale at baseline, provides additional prognostic information for patients with IPF.