Abstract Body (Do not enter title and authors here): Introduction
About 10% of peripheral artery disease (PAD) patients develop claudication, with African Americans at higher risk and more severe symptoms. While supervised exercise therapy (SET) is a primary treatment, its uptake is low. We assessed the feasibility and effectiveness of smartphone-delivered home-based exercise therapy (HBET) in improving functional capacity and PAD symptoms in low-resource settings lacking SET.

Methods
We conducted an interim analysis of Smart Step, a pilot randomized trial (1:1 ratio) comparing smartphone-enabled HBET to usual care (UC) in symptomatic PAD patients at Grady Memorial Hospital, a public safety net hospital in Atlanta, GA, from August 2018 to March 2024. The HBET group received virtual exercise coaching, app-based education, messaging, and reminders for 12 weeks. The primary outcome was the change in 6-minute walking distance (6MWD) at 12 weeks. Secondary outcomes included changes in the Walking Impairment Questionnaire (WIQ) and Short Form 36 (SF-36) scores. Data were analyzed using intention-to-treat, with mixed model repeated measures regression assessing the association between 6MWD and treatment.

Results
We screened 102 patients and enrolled 46. To date, 26 (56%) participants have completed the study, 6 (13%) dropped out, and 14 (30%) are pending completion. The mean [SD] age was 63 [12] years, with 50% female and 90% African American. After 12 weeks, the mean 6MWD increased by 15.7 m from a baseline of 336.0 m in the HBET arm (n=13) and decreased by 6.6 from a baseline of 310.2 m in the UC arm (n=13). The between-group difference was 22.4 [95% CI -11.8 – 56.6] m; p=0.19). The WIQ stair climbing score changed by -10.9 in the UC arm vs. 7.1 in the HBET arm (between group difference 17.9 [95% CI 1.1-34.8]; p=0.04), while the other WIQ sub-scores were more similar between groups. The 12-week changes in SF-36 scores were not different by group.

Conclusion
In this preliminary analysis, the HBET arm showed within-group improvements in 6MWD and symptoms after 12 weeks, but most changes were not significantly different when comparing them with the UC arm. Future analyses are pending and will provide the necessary statistical power for a more precise measure of the treatment effects.