Baseline exercise tolerance and perceived dyspnea to identify the ideal candidate to pulmonary rehabilitation: A risk chart in COPD patients

Background: The appropriate criteria for patient selection are still a key issue in the clinical management of patients referred to pulmonary rehabilitation (PR). Methods: We retrospectively analyzed the records of a wide population of 1470 outpatient or inpatients with chronic obstructive pulmonary disease (COPD) referred to standard PR at two specialized Italian centers. Two models of multivariate logistic regression were developed to test the predictive powers of baseline exercise tolerance, namely the distance walked in 6 mins (6MWD), and of baseline dyspnea on exertion, measured by the modified Medical Research Council scale (mMRC), versus the minimal clinically important difference (MCID) for the same outcomes. Results: Compared to the category of individuals with 6MWD >350 meters, those patients with 201–350 meters and ≤200 meters showed a higher probability (p<0.001) of predicting a MCID change. Compared to the category of individuals with mMRC 0-1point, all the other categories (2, 3, and 4) also showed a higher probability (p<0.001) of predicting a MCID change. The incorporation of baseline categories of 6MWD and mMRC in a risk chart showed that the percentage of patients reaching MCID in both variables increased as the baseline level of 6MWD decreased and of mMRC increased. Conclusion: This study demonstrates that lower levels of exercise tolerance and greater perceived dyspnea on exertion predict achieving clinically meaningful changes for both these treatment outcomes following PR. A specific risk chart that integrates these two variables may help clinicians to select ideal candidates and best responders to PR.