Predictors of changes in 6-min walking distance following pulmonary rehabilitation in COPD patients: a retrospective cohort analysis.

Abstract

Pulmonary rehabilitation (PR) is fundamental in chronic obstructive pulmonary disease (COPD) management but not all patients may show functional benefits from PR. The aim of this study was to identify predictors of non-response in functional capacity to PR. Observational study. Inpatient pulmonary rehabilitation center. COPD patients. This single center study is a retrospective analysis of data in COPD patients admitted to a PR center between January 2012 and December 2017. Post-PR change in 6-min walking distance (6MWD) was used to determine the functional response to PR. Patients characteristics and pre-PR 6-min walking test responses were analyzed to determine factors associated with post-PR changes in 6MWD. Data from 835 patients were analyzed as well as a subgroup of 190 patients with additional variables available. Eighty percent of the patients showed clinically significant 6MWD improvement post-PR. The predictors of 6MWD response to PR were age, pre-PR 6MWD, pre-PR end-of-test dyspnea and long-term oxygen therapy. Older patients, longer pre-PR 6MWD, higher pre-PR end-of-test dyspnea score and the use of oxygen supplementation were associated with lesser post-PR 6MWD improvement. This study identified four important clinical variables predicting a lack of 6MWD response to PR. Patients with such clinical characteristics may require specific PR modalities to improve their functional benefit.