Post-pulmonary rehabilitation exercise adherence and exercise performance in COPD and ILD

Abstract

Patients with Chronic Obstructive Pulmonary Disease (COPD) maintain the benefits of pulmonary rehabilitation (PR) longer than those with Interstitial Lung Disease (ILD). Whether this is due to physiologic differences or differences in home exercise adherence is unknown. Aims: To assess whether adherence to regular exercise after PR influences exercise performance in patients with COPD and with ILD. Methods: Data were analyzed in all patients referred for cardiopulmonary exercise testing (CPET) from 9/2016 to 1/2017. Patients with COPD or ILD who completed PR were categorized as exercise adherent (E) or non-adherent (NE) at referral. CPET performed by cycle ergometry and spirometry were measured. Multivariate regression assessed the interaction of diagnosis and exercise adherence, controlling for age and BMI, on CPET outcomes. Results: 40 patients were included (20 ILD, 20 COPD, 45% M). Exercise adherence was 55% in both groups. E had higher peak VO2 and workload than NE in both disorders. Peak ETCO2 was significantly higher in patients with NE COPD but lower in NE ILD; peak Ve/VO2 slope was significantly higher in NE ILD but lower in NE COPD. Conclusion: Alveolar hypoventilation with CPET is associated with exercise non-adherence in COPD; alveolar hyperventilation and ventilatory inefficiency with CPET are associated with exercise non-adherence in ILD. Adherence rates were the same in both disorders.