Supplementary Material for: Effect of a Three-Week Inpatient Rehabilitation Program on 544 Consecutive Patients with Very Severe COPD: A Retrospective Analysis

<strong><em>Background:</em></strong> Pulmonary rehabilitation improves exercise capacity, symptoms, and quality of life in chronic obstructive pulmonary disease (COPD) patients, and is therefore recommended in all stages of the disease. However, there are insufficient data on patients with very severe disease. <b><i>Objective:</i></b> To describe the effect of an in-house multidisciplinary pulmonary rehabilitation program on patients with very severe COPD. <b><i>Methods:</i></b> We performed a retrospective analysis of 544 consecutive patients with very severe COPD (FEV<sub>1</sub> 0.97 ± 0.26 l) that underwent an in-house pulmonary rehabilitation program (23.44 ± 4.97 days). The studied outcome parameters were the 6-min walk test (6-MWT), health-related quality of life as analyzed by the COPD Assessment Test (CAT) and a dyspnea score [modified Medical Research Council (mMRC) scale], and lung function [forced expiratory volume in 1 s (FEV<sub>1</sub>) and residual volume (RV)]. <b><i>Results:</i></b> We found significant improvements regarding 6-MWT scores (from 321.93 ± 115.67 to 365.82 ± 111.79 m; p < 0.001), CAT scores (from 23.21 ± 6.75 to 19.57 ± 7.35; p < 0.001), mMRC scale scores (from 3.17 ± 1.14 to 2.81 ± 1.22; p < 0.001), and FEV<sub>1</sub> (from 0.97 ± 0.26 to 1.08 ± 0.33 l; p < 0.001). A number of baseline variables were significantly correlated with the improvements that occurred during the program (Δ): baseline 6-MWT with Δ6-MWT (r = -0.316; p < 0.001), baseline CAT with ΔCAT (r = -0.302; p < 0.001), baseline mMRC with ΔmMRC (r = -0.444; p < 0.001), and baseline RV with ΔRV (r = -0.284; p < 0.001), demonstrating that improvements were more pronounced in patients with worse baseline characteristics. Patients on long-term oxygen therapy (LTOT) exhibited significantly greater improvements regarding CAT than patients not on LTOT. <b><i>Conclusion:</i></b> Patients with very severe COPD exhibit clinically meaningful improvements when undergoing pulmonary rehabilitation.