It is uncertain whether opt-out framing will increase participation in a clinical trial intended to promote physical activity in patients with peripheral artery disease (PAD). This study will test whether opt-in or opt-out framing of study participation upon initial contact affects the proportion of patients who ultimately enroll in the study and the demographic characteristics of enrolled patients.

The GAMEPAD study is a two-arm randomized controlled trial aimed at evaluating whether a home-based walking program with automated coaching augmented with gamification and behavioral economic principles improves functional capacity in patients with PAD. GAMEPAD will be conducted using the Way to Health platform, and patients will enroll and consent for participation online, with available help from a study coordinator by telephone. The present study will leverage the GAMEPAD enrollment process to test whether opt-in or opt-out framing of study participation upon initial contact affects the proportion of patients who ultimately enroll in the GAMEPAD study and the demographic characteristics of enrolled patients.

Eligible patients will be contacted via email to determine their interest in participation in the GAMEPAD study. Patients will be randomized 3:1 to an email message framing trial participation in a standard opt-in manner versus an email message framing trial participation in an opt-out manner.

Patients randomized to opt-in framing will be instructed to visit the Way to Health website to enroll in the GAME PAD study, or to call or email the study coordinator with questions or for assistance in enrolling. Patients randomized to opt-out framing will be informed that a study coordinator will be calling them in the coming days to discuss enrollment in the study.

Baseline characteristics of patients randomized to each framing method will be abstracted from the electronic health record and Penn Data Store, and will include age, sex, race/ethnicity, and medical comorbidities. Whether contacted patients created an account on the Way to Health website and/or ultimately consented for enrollment in the study will be captured.

For all outcomes, we will compare patients initially presented with study participation via opt-in framing versus opt-out framing. The primary outcome will be the proportion of patients that enroll in the GAMEPAD study. We will also report the proportion of enrolled patients that failed to complete the GAMEPAD study among those patients that ultimately enrolled.

Inclusion Criteria:

• At least 18 years of age
• Have been seen in the University of Pennsylvania Health System
• Have an ICD-10 code consistent with peripheral artery disease (I70.2x, I70.3x-I70.7x, I73.9) or peripheral artery disease on their problem list
• Have an email address on file with the University of Pennsylvania Health System

Exclusion Criteria:

• Previously indicated unwillingness to be contacted by email for participation in research studies

24 weeks

Adverse events were collected via participant reports through study surveys at 16 weeks, and 24-weeks or participant reports to study staff through text, email or phone call.