Extra-pulmonary features in COPD patients entering rehabilitation after stratification for MRC dyspnea grade

Experts have stated that referral for rehabilitation of patients with chronic obstructive pulmonary disease (COPD) becomes appropriate when these patients become aware of their disability (e.g. usually grade 3 to 5 on the Medical Research Council (MRC) dyspnea scale). However, patients with MRC dyspnea grade 1/2 may also suffer from extra-pulmonary features, such as abnormal body composition, exercise intolerance and reduced disease-specific health status. In the present study, we have studied whether and to what extent chronic obstructive pulmonary disease (COPD) patients with MRC dyspnea grade 1/2 have extra-pulmonary features compared to patients with grade 3, 4 or 5? Pulmonary function, body composition, 6-min walking distance, peak exercise capacity, anxiety, depression and disease-specific health status have been assessed in 333 outpatients who had been referred for pulmonary rehabilitation. On average, patients with MRC dyspnea grade 1/2 had a better exercise tolerance and disease-specific health status compared to patients with grade 4 or 5. Nevertheless, grade 1/2 patients had a higher prevalence of muscle mass depletion. In addition, these patients did still have aberrant values in one or more of the aforementioned outcomes. On average, patients with MRC dyspnea grade 1/2 may clearly suffer from extra-pulmonary features, indicating the necessity to refer these patients for rehabilitation. Therefore, MRC dyspnea scale alone does not appear to be a suitable measure to identify most patients with COPD who have to be referred for rehabilitation.