Properties of self-paced walking in chronic respiratory disease: A patient goal-oriented assessment

Abstract

Background: Patients with chronic respiratory diseases often have the simple goal of wanting to walk for longer. We evaluated the properties of a patient goal-oriented, symptom-limited, self-paced walk (SPW). Methods: Patients with symptomatic chronic respiratory disease, referred for a 6-week course of pulmonary rehabilitation (PR), were screened for eligibility. Baseline assessments included two SPWs with both time and speed measured, two 6-min walk tests (6MWTs), and the Medical Research Council dyspnea scale. On program completion, two SPWs and one 6MWT were performed. The repeatability, responsiveness, and validity of the SPW were assessed. Results: Two SPWs were completed by 50 and 37 patients before and after rehabilitation, respectively. The speed (r = -0.54, P < .001) but not the time (r = -0.23, P = .19) of the SPW correlated with Medical Research Council dyspnea grade. The mean SPW time increased on the second day of testing from 15.1 ± 8.4 min to 17.9 ± 7.7 min (P = .004), and the effect of test day was unaltered by PR (P = .80). The coefficient of repeatability for SPW time was 16.1 min. Both the mean SPW time (10.6 min; 95% CI, 6.6-14.5 min; P < .001) and the mean speed (3.5 m/min; 95% CI, 1.3-5.7 m/min; P < .01) increased after rehabilitation. Conclusions: The SPW time is an easily understandable, patient goal-oriented assessment with construct validity that is highly responsive to the effects of PR. The variability in SPW time makes it better suited to interpreting group rather than individual changes. Trial registry: ClinicalTrials.gov; No.: NCT00781183; URL: www.clinicaltrials.gov. © 2011 American College of Chest Physicians.