Magnitude of exercise capacity and quality of life improvement following repeat pulmonary rehabilitation in patients with COPD

Background: Maintenance and repeated pulmonary rehabilitation programs (PRPs) for patients with COPD have attempted to prolong PRP benefits beyond 12-24 months. However, there is limited evidence as to the magnitude of benefit or the ideal interval between repeating the program under "real-world" conditions in which patients are referred based on clinical necessity. Therefore, we reviewed the effects of repeating PRP in a physician-referred cohort of patients with COPD. Methods: A total of 141 individuals with COPD completed PRP twice and 35 completed PRP three times over a 12-year period. We used linear mixed-effects models to quantify the magnitude and change in 6-minute walk distance (6MWD), St George's Respiratory Questionnaire (SGRQ), and Hospital Anxiety and Depression Scale (HADS) for each PRP. One-way analysis of variance with Tukey's post hoc analysis compared the effects of different time intervals on 6MWD, SGRQ, and HADS between PRPs. Results: Despite 39 mL/year average decrease in forced expiratory volume in 1 second, overall 6MWD improved following each PRP (PRP1=58 m, P<0.0001; PRP2=42 m, P<0.0001; PRP3=32 m, P<0.003). Mean SGRQ decreased after PRP1 (-7.0 units; P<0.001) and PRP2 (-4.9 units; P<0.0001) but not after PRP3 (-3.2 units; P=0.10). HADS decreased after PRP1 (-1.9 units; P<0.0001) and PRP2 (-1.7 units; P=0.0001) but not after PRP3 (-0.4 units; P=0.63). Conclusion: In physician-referred patients who underwent repeat PRP as clinically required, there were clear benefits in functional exercise capacity following each repeat PRP, which was not affected by the time interval between PRPs. Health-related quality of life and mood improved after the first two PRPs, but not after a third.