A Positive Psychology-Motivational Interviewing Intervention to Promote Positive Affect and Physical Activity in Type 2 Diabetes: The BEHOLD-8 Controlled Clinical Trial

Objective: Physical activity is associated with superior health outcomes in patients with type 2 diabetes (T2D), but most T2D patients do not follow physical activity recommendations. The objective of this study was to assess the feasibility and impact of a novel combined positive psychology-motivational interviewing (PP-MI) intervention to promote physical activity in T2D. Methods: This controlled clinical trial compared an 8-week, phone-delivered PP-MI intervention to an attention-matched MI-enhanced behavioral counseling condition among 60 participants with T2D and suboptimal moderate to vigorous physical activity (MVPA; <150 min/wk). The primary study outcome was feasibility (proportion of sessions completed) and acceptability (0-10 ease and utility ratings of each session). Secondary outcomes were between-group differences in changes in positive affect (main psychological outcome) and accelerometer-measured physical activity (MVPA and steps per day), using mixed-effects regression models, at 8 and 16 weeks. Results: Ninety-two percent of PP-MI sessions were completed, and mean participant ratings of ease/utility were 8.5 to 8.8/10, surpassing a priori benchmarks for feasibility and acceptability. PP-MI participants had small-medium effect size (ES) difference improvements in positive affect compared with MI (8 weeks: estimated mean difference [EMD] = 3.07 [SE = 1.41], p = .029, ES = 0.44; 16 weeks: EMD = 2.92 [SE = 1.73], p = .092, ES = 0.42). PP-MI participants also had greater improvements in MVPA (8 weeks: EMD = 13.05 min/d [SE = 5.00], p = .009, ES = 1.24; 16 weeks: EMD = 7.96 [SE = 4.53], p = .079, ES = 0.75), with similar improvements in steps per day. Conclusions: The PP-MI intervention was feasible and well accepted. Next-step efficacy studies can more rigorously explore the intervention's effects on physical activity and clinical outcomes.