Characteristics of people with PAD identified with ankle brachial index testing in three U.S. cities

Description of Background: The extent and significance of clinically undiagnosed PAD is unclear. As part of recruitment for randomized clinical trials of people with lower extremity peripheral artery disease (PAD), these analyses compared characteristics of people with PAD (ankle brachial index (ABI) < 0.90) identified using mailed postcards in three U.S. cities to patients with established PAD identified from medical centers in the same three cities.

Methods: To recruit people with PAD for randomized clinical trials, mailing lists were purchased and postcard advertisements were mailed to people age 50 and older living in Chicago, Minneapolis, and New Orleans. The postcards invited people with “difficulty walking” and cardiovascular risk factors to call a telephone number to learn about randomized clinical trials testing interventions for people with PAD. Individuals with difficulty walking who were interested in clinical trial participation were invited to attend a study visit for ABI testing. Patients with established PAD from medical centers in the same cities were also invited to participate in the randomized trials. All participants underwent evaluation that included walking performance measures and medical history.

Results: Of 2,431 identified from the community who underwent ABI testing, 499 (20.5%) had an ABI < 0.90, consistent with PAD. Characteristics of these 499 people were compared to 184 with PAD identified from a medical center in the same three cities.

Conclusion: 20.5% of people in three US metropolitan cities identified using mailed postcards who reported walking difficulty had an ABI < 0.90 consistent with PAD. Compared to people with PAD identified from a medical center in the same three cities, those with PAD identified from the community had significantly greater walking impairment and included a higher proportion of people who were Black.

Learning Objective: 1. Identify the proportion of people with ABI < 0.90 among people identified using mailed postcards who reported walking difficulty.
2. Describe differences in characteristics of people with ABI < 0.90 identified from a community setting, compared to those in a medical center setting.