Duration of Supervised Exercise Necessary for Meaningful Improvement in Peripheral Artery Disease.

Background: Supervised treadmill exercise improves walking performance in people with lower extremity peripheral artery disease, but benefits are not immediate. This study identified the time course of attaining meaningful improvement in 6-minute walk distance and patient-reported outcome measures during a 6-month supervised exercise intervention in people with peripheral artery disease.

Methods: Participants with peripheral artery disease were randomized to supervised treadmill exercise 3 time weekly or a nonexercise control group for 6 months. Six-minute walk distance (large clinically important difference: 20 meters) and the Walking Impairment Questionnaire distance score (0-100 scale, 100 is best, clinically important difference: 5 points) were measured at the 6-week, 12-week, and 26-week follow-up using a mixed-effects model for repeated measures.

Results: Of 210 randomized participants (mean age, 67.0±8.6 years, 82 [39%] women, 141 [66%] Black), 200 (95%) completed at least 1 follow-up visit. Compared with controls, supervised exercise significantly improved 6-minute walk distance by 13.0 m (=0.049) at the 6-week, 31.8 m (<0.001) at the 12-week, and 33.9 m (<0.001) at the 26-week follow-up. Compared with controls, supervised exercise increased the Walking Impairment Questionnaire distance score by +2.63 (=0.37) at the 6-week, +6.59 (=0.049) at the 12-week, and +2.37 (=0.49) at the 26-week follow-up.

Conclusions: In people with peripheral artery disease, >6 weeks of supervised treadmill exercise was necessary to attain a large meaningful gain in 6-minute walk, and large meaningful gains were measurable by week 12 of supervised exercise. Meaningful improvement in participant reported walking ability was first observed at the 12-week follow-up, but this statistically significant benefit was gone by the 26-week follow-up.

Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01408901.