Comorbidity clusters and changes in exercise capacity and health status following pulmonary rehabilitation (PR) in patients with COPD

Background: The impact of comorbidities on changes in relevant outcomes following PR in COPD is unclear. We aimed to study the impact of comorbidity clusters on changes in exercise capacity and health status in patients with COPD undergoing PR. Methods: 213 patients (59% men; age 64±7 yrs; FEV1 51±17% pred) were previously classified into 5 clusters of objectively identified comorbidities: cluster 1 (n=67, less comorbidity), 2 (n=49, cardiovascular), 3 (n=44, cachectic), 4 (n=33, metabolic), or 5 (n=20, psychologic) (Vanfleteren et al. Am J Respir Crit Care Med 2013). Patients underwent state-of-the-art PR. 6-min walk test (6MWT), constant work rate test (CWRT) and St. George's Respiratory Questionnaire (SGRQ) were assessed before and after PR. Results: Table 1 presents the responses to PR. ![Figure][1] The proportion of patients above the minimum clinically important difference (MCID) for the 6MWT (≥25m) was higher in cluster 5 (84%) than in clusters 1 (44%), 2 (49%) and 4 (39%) ( P <0.05 for all), but no differences were found for the CWRT (≥100s) or SGRQ (≥4 units). Significant results from logistic regression models are presented in Table 2. Conclusions: Comorbidity clusters can impact relevant outcomes in patients with COPD undergoing PR. Exercise capacity and health status are differently influenced by these clusters. Subjects with anxiety or depression may benefit more from PR. [1]: pending:yes