Predictors of Change in Exercise Capacity after Simple outpatient-based Pulmonary Rehabilitation in Patients with Chronic Obstructive Pulmonary Disease

Abstract

Introduction: Patients with chronic obstructive pulmonary disease (COPD) often experience decreased exercise capacity and quality of life (QoL). Pulmonary rehabilitation programs (PRPs) can improve exercise capacity, QoL and dyspnea in COPD patients, but little is known about the predictive factors associated with the change in exercise capacity after PRPs. The aims of this study were to confirm the benefits of PRPs and define the predictive factors associated with the change in exercise capacity after PRPs. Methods: 43 patients of COPD were arranged to our PRPs. The baseline and post-PRP status were evaluated with spirometry, 6MWD, cardiopulmonary exercise test, and St. George's Respiratory Questionnaire (SGRQ). Stepwise multiple regression analysis was used to evaluate factors predictive of change in the 6MWD. Results: After 6 weeks of PRPs, there were significant improvements in 6MWD (from 461.1±86.2 m to 505.5±78.4 m, p＜0.001), peak VO2 (from 15.0±3.8 ml/min/kg to 16.8±4.2 ml/min/kg, p＜0.05), maximal work rate (from 73.5±22.3 watt to 78.0±22.0 watt, p ＜0.05) and scores on the SGRQ (total, activity, symptoms and impact, all p＜0.001). Stepwise multiple regression analysis revealed that SGRQ activity, body weight, age, peak oxygen pulse (O2P) and PETCO2 were significant determinants of change in exercise capacity. Conclusions: PRPs are effective in patients with COPD in increasing exercise capacity and QoL. Baseline SGRQ activity, body weight, age, peak O2P and PETCO2 significantly contribute to the change in exercise capacity after PRPs.