Using pedometers to monitor walking activity in outcome assessment for pulmonary rehabilitation

Abstract

The purpose of this study was to determine whether a commercially available pedometer could detect changes in home-based walking activity among chronic obstructive pulmonary disease (COPD) patients completing pulmonary rehabilitation (PR). Patients with COPD referred to outpatient PR wore a pedometer to count steps for 1 week at the beginning and 1 week at the end of PR. Patients also completed the 6-min walk test (6MWT), the Medical Research Council (MRC) dyspnea scale and the self-administered chronic respiratory disease questionnaire (CRQ) at the beginning and the end of PR. Paired t tests were used to compare pre- and post-PR changes in outcome variables. 45 patients with severe COPD (forced expiratory volume in 1 second [FEV(1)] 45% +/- 18% of predicted) participated in a total of 17.4 +/- 4.6 PR sessions. Significant improvements in 6MWT (49 +/- 59 m; p < .0001), MRC dyspnea score (-0.64 +/- 0.96 units; p = .003) and CRQ score (10 +/- 18 units; p = .0007) were noted following PR. Patients whose pedometer-measured steps were within 20% of observed counted steps were included in the analysis. Pedometer counts increased by 33 +/- 149 steps per hour worn after, as compared with before PR (p = .14). There was a significant inverse relationship between baseline pedometer counts and change in pedometer counts per hour post-PR (r = -.46; p = .001). Patients with low baseline activity levels had significant increases in pedometer activity (88 +/- 30 counts per hour worn) and a greater reduction in MRC dyspnea score (-0.94 vs -0.29; p = .04) following PR, whereas those with higher baseline activity levels had a decrease in pedometer activity (-19 +/- 29 counts/hour; p = .015). A standard pedometer worn at the waist did not detect changes in lower extremity activity following PR. This negative finding occurred despite demonstrated improvements in dyspnea, exercise tolerance and quality of life measures. Although pedometers are inexpensive and easy to use, they may not be sensitive enough to be used routinely as an outcome measure for PR.