MOSAIC: Home Intervention Boosts Walking Time in PAD Patients

Patients with PAD can improve their walking distance with minimal assistance from physical therapists when the focus is on building motivation and commitment to walking exercise, according to results from the randomized MOSAIC study. The idea is to help them better understand and take ownership of their condition and treatment.

“The systematic application of behavior-change strategies really moves forward our understanding of how to help patients start and continue to do walking exercise at home,” lead study author Lindsay M. Bearne, PhD (Kingston University and St George’s, University of London, England), told TCTMD.

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May 10, 2022

Patients randomized to a combination of in-person and phone instruction with physical therapists, plus support items such as pedometers, exercise diaries, and worksheets, were able to walk an average of 16.7 meters farther on the 6-minute walk test than the usual-care group at 3 months of follow-up (P = 0.009).

“The fact that it increased people's walking capacity at 3 months is important, but we also found that people's attitudes toward walking exercise as a treatment for their condition had changed for the positive, as had their illness representation, or how they understood and made sense of their condition,” Bearne noted.

In an editorial accompanying the study in JAMA, Mary M. McDermott, MD (Northwestern University Feinberg School of Medicine, Chicago), says developing home-based exercise programs into first-line therapy for PAD patients is an imperative.

“A highly effective home-based exercise program has the potential to help millions of people with PAD, including those in rural areas without access to supervised exercise therapy and those unable to travel regularly to the facility to participate,” McDermott writes. “By avoiding the need for an exercise facility or a coach during each exercise session, home-based exercise programs are likely to be less costly than supervised exercise.”

The MOSAIC Intervention

Bearne and colleagues included 190 patients age 50 and older from the vascular clinics of six public hospitals in England between January 2018 and March 2020. All had PAD and intermittent claudication. Patients randomized to the intervention group (n = 95) had two 60-minute in-person sessions with a physical therapist in week 1 and week 2 plus a 20-minute phone call with a physical therapist in week 6 and again in week 12. The therapists were instructed in motivational interviewing approaches guided by behavior change principles, with the ultimate goal of having patients continue their walking independently when the study ended.

The primary outcome of 6-minute walk distance at 3 months improved from a mean of 352.9 meters at baseline to 380.6 meters in the intervention group, and from 369.8 meters at baseline to 372.1 meters at 3 months in the usual-care group. Similarly, in per protocol analyses, the intervention group had a 19.2-meter advantage on the 6-minute walk test distance compared with the usual-care group (P = 0.004).

However, some secondary outcomes, which included a self-reported maximum walking distance questionnaire, activities of daily living, and health-related quality of life, were not significantly different between the intervention and usual-care groups at 6 months.

Walking Intensity and Communication

“In contrast with the RCTs that demonstrated larger effects of home-based walking exercise for people with PAD, the trial by Bearne et al included fewer in-person visits and did not objectively monitor intensity of walking exercise, which may have lessened the potency of the home-based exercise intervention,” McDermott notes.

To TCTMD, Bearne said after the study was over, the investigators learned through listening to the taped sessions that during the phone calls, some physical therapists delivered a lower-than-expected percentage of mandatory instructional components of the program.

“Some of them told us that they found that it was more difficult to deliver the sessions over the telephone. They were missing out on some of the nonverbal feedback that they otherwise would have been able to see,” she added. “They also felt unfamiliar with this way of treating patients, but this study was mostly done before the pandemic, so I think it’s possible some of that unfamiliarity may have changed.”

As for exercise intensity, McDermott was the lead author of the LITE trial, which found that home-based walking to an intensity where ischemic leg pain was induced was more likely to improve 6-minute walk times in PAD patients than pain-free walking at a comfortable pace. In fact, the comfortable-paced walkers in that study actually had no improvement in 6-minute walk time compared with a control group who did not exercise.

Bearne agreed that exercise intensity in home-based walking programs is potentially important to outcomes and said it’s likely that some of the MOSAIC patients were not walking at sufficient intensity to gain longer-term benefits in the other secondary measures that were not significantly different compared with usual care.