Classification of People with Chronic Respiratory Disease into Preserved or Reduced Functional Exercise Capacity: A Retrospective Analysis of Associated Factors Considering Baseline Characteristics and Responses to Pulmonary Rehabilitation

Abstract

Purpose: To classify individuals with chronic respiratory disease (CRD) into preserved or reduced functional exercise capacity (FEC) using the baseline 6-minute walk distance (6MWD), as well as to compare between these two groups other baseline characteristics, physiological and symptomatologic responses to the baseline 6-minute walk test (6MWT), and responses in health-related quality of life (HRQoL) and FEC to pulmonary rehabilitation (PR). Method: Sociodemographic and clinical data, lung function, HRQoL, and FEC (6MWT) from individuals with CRD who participated in a PR program were analyzed. Individuals were classified as with preserved or reduced FEC, if 6MWD was ≥ or < the lower limit of normality, respectively. Results: We included 117 individuals (50% male, age 61 years, 39% with chronic obstructive pulmonary disease), 76 classified as preserved FEC and 41 as reduced FEC. Individuals with reduced FEC had the lowest values for weight and lung function. No statistical difference was found when comparing the changes in HRQoL and 6MWD after PR between the preserved and reduced FEC groups. However, the mean 6MWD change in the reduced FEC group (61m) was twice the change in the preserved FEC group (30m). Conclusions: The classification into preserved or reduced FEC proved to be useful in PR as it allowed to identify individuals with CRD with lower weight and lung function at baseline, but who seemed to benefit more from the program.