Peripheral artery disease: motivational support under study to improve walking

Human support compared with an app

Participants, recruited from the community in Wichita, Kansas, were randomly assigned to two groups: 16 received motivational interviewing face to face or by phone, and 13 used a smartphone app.

The primary outcome was the change in distance covered during a six-minute walk test. Weight change was a secondary outcome. According to the abstract provided, motivational interviewing had been more effective than the app on both outcomes after three months. However, the magnitude of this between-group advantage is not reported.

An analysis focused on social differences

This secondary analysis explores links between outcomes and several social or demographic characteristics: education level, income, family circumstances, social contact or unmet daily needs. Its aim is to generate hypotheses about differences in response to support.

For walking, the authors report a difference in median changes of 44 meters between the category grouping other racial and ethnic identities and non-Hispanic white participants. This figure is not the average gain attributable to motivational interviewing compared with the app. Nor does the abstract establish which social characteristic might explain this difference.

No statistically significant difference in weight loss was observed between the social strata studied. Before-and-after improvements appear in several subgroups, but on their own they do not demonstrate that these subgroups benefit more from the intervention.

What these findings tell us

The practical value of this work is that it raises the question of tailoring support to patients’ circumstances. The authors suggest understanding health information and social support as possible explanations, among others. These mechanisms remain hypotheses, not demonstrated mediating factors.

The small sample and numerous exploratory comparisons make the subgroup findings fragile. This study therefore cannot be used to select support based on ethnicity or to conclude that an app is generally less useful than human support.

Finally, the findings concern patients with peripheral artery disease. They cannot be directly extrapolated to healthy people looking to increase their physical activity.

What we can take away

Motivational interviewing shows a favorable signal in this small trial. The influence of social context on its benefits remains to be confirmed in larger studies.