The effect of body mass index on pulmonary rehabilitation outcomes in patients with chronic obstructive pulmonary disease

CONTEXT: Although pulmonary rehabilitation (PR) is increasingly used in patients with chronic obstructive pulmonary disease (COPD), the factors affecting the gains obtained from PR are still not clear.
AIMS: We aimed to investigate the effect of body mass index (BMI) on PR outcomes in COPD.
SETTINGS AND DESIGN: The study was a retrospective–descriptive study.
SUBJECTS AND METHODS: Patients with BMI of 18.5–25 kg/m2 were referred to as Group 1 (n = 15) and patients with BMI ≥25 kg/m2 as Group 2 (n = 17). All patients received PR for 8 weeks. Six‑min walking distance (6MWD), forced expiratory volume in 1‑s, forced vital capacity (FVC), carbon monoxide diffusing capacity (DLCO), maximal inspiratory pressure (MIP), modified Medical Research Council dyspnea scale (mMRC), and COPD assessment test (CAT) scores were compared.
STATISTICAL ANALYSIS USED: Paired t‑test, Wilcoxon rank, and Mann–Whitney‑U test were used for statistical analysis.
RESULTS: Thirty‑two patients were included in the study. Baseline parameters were similar except 6MWD. Following PR, 6MWD, mMRC, and CAT scores were significantly improved in both the groups (P < 0.05). A significant difference was found in favor of Group 1 for FVC (P = 0.039) and MIP (P = 0.018), while no difference was detected in DLCO.
CONCLUSIONS: In this study, PR yielded similar gains between COPD patients with high BMI and those with normal BMI in terms of exercise capacity, dyspnea, and disease symptom severity. The only additional gains were achieved in the respiratory functions of patients with normal weight. All COPD patients should be referred to PR, regardless of the BMI, taking into account the resulting PR gains