Effect of a Home-Based, Walking Exercise Behavior Change Intervention vs Usual Care on Walking in Adults With Peripheral Artery Disease: The MOSAIC Randomized Clinical Trial

Abstract

Importance: Home-based walking exercise interventions are recommended for people with peripheral artery disease (PAD), but evidence of their efficacy has been mixed.

Objective: To investigate the effect of a home-based, walking exercise behavior change intervention delivered by physical therapists in adults with PAD and intermittent claudication compared with usual care.

Design, setting, and participants: Multicenter randomized clinical trial including 190 adults with PAD and intermittent claudication in 6 hospitals in the United Kingdom between January 2018 and March 2020; final follow-up was September 8, 2020.

Interventions: Participants were randomized to receive a walking exercise behavior change intervention delivered by physical therapists trained to use a motivational approach (n = 95) or usual care (n = 95).

Main outcomes and measures: The primary outcome was 6-minute walking distance at 3-month follow-up (minimal clinically important difference, 8-20 m). There were 8 secondary outcomes, 3 of which were the Walking Estimated Limitation Calculated by History (WELCH) questionnaire (score range, 0 [best performance] to 100), the Brief Illness Perceptions Questionnaire (score range, 0 to 80 [80 indicates negative perception of illness]), and the Theory of Planned Behavior Questionnaire (score range, 3 to 21 [21 indicates best attitude, subjective norms, perceived behavioral control, or intentions]); a minimal clinically important difference was not defined for these instruments.

Results: Among 190 randomized participants (mean age 68 years, 30% women, 79% White race, mean baseline 6-minute walking distance, 361.0 m), 148 (78%) completed 3-month follow-up. The 6-minute walking distance changed from 352.9 m at baseline to 380.6 m at 3 months in the intervention group and from 369.8 m to 372.1 m in the usual care group (adjusted mean between-group difference, 16.7 m [95% CI, 4.2 m to 29.2 m]; P = .009). Of the 8 secondary outcomes, 5 were not statistically significant. At 6-month follow-up, baseline WELCH scores changed from 18.0 to 27.8 in the intervention group and from 20.7 to 20.7 in the usual care group (adjusted mean between-group difference, 7.4 [95% CI, 2.5 to 12.3]; P = .003), scores on the Brief Illness Perceptions Questionnaire changed from 45.7 to 38.9 in the intervention group and from 44.0 to 45.8 in the usual care group (adjusted mean between-group difference, -6.6 [95% CI, -9.9 to -3.4]; P < .001), and scores on the attitude component of the Theory of Planned Behavior Questionnaire changed from 14.7 to 15.4 in the intervention group and from 14.6 to 13.9 in the usual care group (adjusted mean between-group difference, 1.4 [95% CI, 0.3 to 2.5]; P = .02). Thirteen serious adverse events occurred in the intervention group, compared with 3 in the usual care group. All were determined to be unrelated or unlikely to be related to the study.

Conclusions and relevance: Among adults with PAD and intermittent claudication, a home-based, walking exercise behavior change intervention, compared with usual care, resulted in improved walking distance at 3 months. Further research is needed to determine the durability of these findings.

Trial registrations: ISRCTN Identifier: 14501418; ClinicalTrials.gov Identifier: NCT03238222.

Figure 1.. Flow of Participants Through the MOSAIC Randomized Trial of a Walking Exercise Behavior Change Intervention in Adults With Peripheral Artery Disease

MOSAIC indicates Motivating Structured Walking Activity in People With Intermittent Claudication. ^aRandomization took place after participants provided written consent and completed baseline testing.

Figure 2.. Baseline, 3-Month Follow-up, and Change in 6-Minute Walk Distance at 3 Months Among Adults With Peripheral Artery Disease

A, Each vertical line represents an individual participant, with participants ordered by baseline value and the vertical line extending up (improvement) or down (deterioration) to the 3-month value. B, Vertical lines extending up denote the degree of improvement in 6-minute walk distance at 3-month follow-up. Vertical lines extending down denote the degree of decline in 6-minute walk distance. C, Each point represents an individual participant. The vertical distance between the 2 regression lines represents the estimated difference between the groups from the analysis of covariance between baseline and 3 months.