Perceived versus objective change in walking ability in peripheral artery disease: Results from 3 randomized clinical trials of exercise therapy

BACKGROUND: In people with lower-extremity peripheral artery disease, the effects of exercise on patient-reported outcomes remain unclear. METHODS AND RESULTS: Four hundred four people with peripheral artery disease in 3 clinical trials were randomized to exercise (N=205) or a control group (N=199) and completed the 6-minute walk and the Walking Impairment Questionnaire distance score (score 0–100, 100=best) at baseline and 6-month follow-up. Compared with the control group, exercise improved 6-minute walk distance by +39.8 m (95% CI, 26.8– 52.8, P<0.001) and the Walking Impairment Questionnaire distance score by +7.3 (95% CI, 2.4–12.1, P=0.003). In all, 2828 individual Walking Impairment Questionnaire distance score questions were completed at baseline and follow-up. Among participants who perceived no change in ability to walk 1 or more distances between baseline and follow-up, 6-minute walk improved in the exercise group and declined in the control group (+26.8 versus −6.5 m, P<0.001). Among participants who perceived that their walking ability worsened for 1 or more distances between baseline and follow-up, the 6-minute walk improved in the exercise group and declined in the control group (+18.4 versus – 27.3 m, P<0.001). Among participants who reported worsening calf symptoms at follow-up, the exercise group improved and the control group declined (+28.9 versus −12.5 m, P<0.01). CONCLUSIONS: In 3 randomized trials, exercise significantly improved the 6-minute walk distance in people with peripheral artery disease, but many participants randomized to exercise reported no change or decline in walking ability. These findings suggest a significant discrepancy in objectively measured walking improvement relative to perceived walking improvement in people with peripheral artery disease.