Cardiopulmonary Exercise Test, mMRC and GAP score Can Predict 1-year Mortality in Patients with Idiopathic Pulmonary Fibrosis: A Prospective Study

Abstract

Idiopathic pulmonary fibrosis (IPF) is a rare lung disease with high mortality. Finding an effective predictor of survival is therefore important for both clinicians and patients. In this prospective observational study, we evaluated the prognostic value of the parameters of cardiopulmonary exercise test (CPET), pulmonary function test (PFT), 6-min walk test (6MWT), and certain questionnaires on mortality in Asian patients with IPF. A total of 34 patients diagnosed with IPF were enrolled and followed up for 12 months, during which 6 patients died. The non-survivors had significantly higher minute ventilation to carbon dioxide output (VE/VCO2) slope, more oxygen desaturation during CPET and 6MWT, less heart rate recovery one minute after CPET, higher dead space, higher Gender-Age-Physiology (GAP) index and Modified Medical Research Council (mMRC) score. GAP index, mMRC score, VE/VCO2 slope, and end-tidal partial pressure of carbon dioxide (PETCO2) at maximal exercise demonstrated an area under curve (AUC) of >0.7, and the corresponding cutoff values were 4, 2, 35.1 and 3.6 kPa. Therefore, GAP index, mMRC scores, VE/VCO2 slope, and PETCO2 at maximal exercise could be important predictors for mortality in Asian patients with IPF.