Effect of Low-Intensity vs High-Intensity Home-Based Walking Exercise on Walk Distance in Patients With Peripheral Artery DiseaseThe LITE Randomized Clinical Trial

Question  Does a low-intensity (does not induce ischemic leg symptoms) home-based walking exercise intervention improve 6-minute walk distance more than a high-intensity (induces ischemic leg symptoms) home-based walking exercise intervention and does the low-intensity intervention improve 6-minute walk distance more than a nonexercise control (weekly health educational sessions only) among patients with lower-extremity peripheral artery disease (PAD)?

Findings  In this multicenter randomized clinical trial that included 305 participants with PAD, low-intensity exercise, high-intensity exercise, and nonexercise control resulted in a mean 12-month change in 6-minute walk distance of −6.4 m, 34.5 m, and −15.1 m, respectively. Low-intensity exercise was significantly less effective than high-intensity exercise and was not significantly different from the nonexercise control.

Meaning  These findings do not support the use of low-intensity walking exercise for patients with PAD.

Importance  Supervised high-intensity walking exercise that induces ischemic leg symptoms is the first-line therapy for people with lower-extremity peripheral artery disease (PAD), but adherence is poor.

Objective  To determine whether low-intensity home-based walking exercise at a comfortable pace significantly improves walking ability in people with PAD vs high-intensity home-based walking exercise that induces ischemic leg symptoms and vs a nonexercise control.

Design, Setting, and Participants  Multicenter randomized clinical trial conducted at 4 US centers and including 305 participants. Enrollment occurred between September 25, 2015, and December 11, 2019; final follow-up was October 7, 2020.

Interventions  Participants with PAD were randomized to low-intensity walking exercise (n = 116), high-intensity walking exercise (n = 124), or nonexercise control (n = 65) for 12 months. Both exercise groups were asked to walk for exercise in an unsupervised setting 5 times per week for up to 50 minutes per session wearing an accelerometer to document exercise intensity and time. The low-intensity group walked at a pace without ischemic leg symptoms. The high-intensity group walked at a pace eliciting moderate to severe ischemic leg symptoms. Accelerometer data were viewable to a coach who telephoned participants weekly for 12 months and helped them adhere to their prescribed exercise. The nonexercise control group received weekly educational telephone calls for 12 months.

Main Outcomes and Measures  The primary outcome was mean change in 6-minute walk distance at 12 months (minimum clinically important difference, 8-20 m).

Results  Among 305 randomized patients (mean age, 69.3 [SD, 9.5] years, 146 [47.9%] women, 181 [59.3%] Black patients), 250 (82%) completed 12-month follow-up. The 6-minute walk distance changed from 332.1 m at baseline to 327.5 m at 12-month follow-up in the low-intensity exercise group (within-group mean change, −6.4 m [95% CI, −21.5 to 8.8 m]; P = .34) and from 338.1 m to 371.2 m in the high-intensity exercise group (within-group mean change, 34.5 m [95% CI, 20.1 to 48.9 m]; P < .001) and the mean change for the between-group comparison was −40.9 m (97.5% CI, −61.7 to −20.0 m; P < .001). The 6-minute walk distance changed from 328.1 m at baseline to 317.5 m at 12-month follow-up in the nonexercise control group (within-group mean change, −15.1 m [95% CI, −35.8 to 5.7 m]; P = .10), which was not significantly different from the change in the low-intensity exercise group (between-group mean change, 8.7 m [97.5% CI, −17.0 to 34.4 m]; P = .44). Of 184 serious adverse events, the event rate per participant was 0.64 in the low-intensity group, 0.65 in the high-intensity group, and 0.46 in the nonexercise control group. One serious adverse event in each exercise group was related to study participation.

Conclusions and Relevance  Among patients with PAD, low-intensity home-based exercise was significantly less effective than high-intensity home-based exercise and was not significantly different from the nonexercise control for improving 6-minute walk distance. These results do not support the use of low-intensity home-based walking exercise for improving objectively measured walking performance in patients with PAD.

Trial Registration  ClinicalTrials.gov Identifier: NCT02538900