Low- and high-intensity home-based walking exercise in patients with peripheral artery disease
Background: In patients with peripheral artery disease (PAD), supervised high-intensity walking exercise that induces ischemic leg symptoms (intermittent claudication) is a first-line therapy, but adherence has been limited. This study assessed whether an alternative approach, with a low-intensity home-based walking exercise program that does not induce ischemic leg symptoms but would be more acceptable to patients, is associated with similar effects.
Methods: Patients with PAD were randomly allocated to undergo a low-intensity walking exercise (n = 116), high-intensity walking exercise (n = 124), or no-exercise (n = 65) program for 12 months. In both exercise groups patients were asked to walk 5 times per week for up to 50 minutes per session while wearing an accelerometer that would document exercise intensity and time. The low-intensity group walked at a pace that did not cause ischemic leg symptoms; the high-intensity group walked at a pace that would elicit moderate to severe ischemic leg symptoms. Accelerometer data were viewable to an exercise coach who contacted patients each week for 12 months to assist with adherence to the high- and low-intensity exercise programs. The no-exercise group received weekly educational telephone calls for 12 months. The primary study outcome was the mean change in 6-minute walk distance at 12 months, with a minimum clinically important difference defined as 8 m to 20 m.
Results: There were 305 patients (mean age, 69.3 years; 146 [47.9%] women) enrolled, of whom 82% completed the 12-month follow-up. Compared with baseline, the 6-minute walk distance decreased from 332.1 m to 327.5 m in the low-intensity exercise group (mean change: -6.4 m [95% CI, -21.5 to 8.8]) and increased from 338.1 m to 371.2 m in the high-intensity group (mean change: 34.5 m [95% CI, 20.1-48.9]), with a mean change for the between-group comparison of -40.9 m (97.5% CI, -61.7 to -20.0; P < .001). The 6-minute walk distance decreased from 328.1 m at baseline to 317.5 m at 12 months in the no-exercise group (mean change, -15.1 m [95% CI, -35.8 to 5.7]), which was not significantly different from the change reported in the low-intensity exercise group. There was no significant difference in the number of serious adverse events between the low-intensity, high-intensity, and no-exercise groups.
Conclusions: The authors concluded that the study results do not support the use of an easy-to-adopt, low-intensity home-based walking exercise for improving walking performance in patients with PAD, as the low-intensity exercise program did not significantly differ from the no-exercise approach and the high-intensity group had a clearly improved walking distance.
McMaster editors' comment: In a related study by the same research group, a home-based exercise program that incorporated a wearable activity monitor and telephone coaching did not confer significant improvement in walking performance as compared with usual care in patients with PAD (doi: 10.1001/jama.2018.3275). Taken together, these findings confirm clinicians’ impression that lifestyle interventions are challenging in patients with PAD but should not deter efforts at an individual level aimed at promoting physical activity and smoking cessation.