Abstract
BACKGROUND: The majority of persons with type 2 diabetes (T2D) do not meet recommended levels of physical activity, despite clear links between physical activity and superior medical outcomes in this population. The objective of this trial was to assess the feasibility and impact of a novel 16-week combined positive psychology-motivational interviewing (PP-MI) program to promote physical activity among inactive persons with T2D. METHODS: This pilot randomized trial compared the 16-week, phone-delivered PP-MI intervention to an attention-matched diabetes counseling condition among 70 persons with T2D and low levels of baseline moderate to vigorous physical activity (MVPA; <150 min/week). The primary study outcomes were feasibility (assessed via rates of session completion) and acceptability (assessed via mean participant ratings [0-10] of the ease and utility of weekly sessions). Key secondary outcomes included between-group differences in improvement in positive affect, other psychological outcomes, and accelerometer-measured physical activity, assessed using mixed effects regression models, at 16 and 24 weeks. RESULTS: Participants completed a mean 11.0 (SD 4.4; 79%) of 14 PP-MI phone sessions, and composite mean ratings of ease/utility were 8.6/10, above our a priori benchmarks for feasibility/acceptability (70% session completion; 7.0/10 mean ratings). PP-MI participants had small to medium effect size (ES) difference improvements in MVPA (ES difference = 0.34) and steps/day (ES difference = 0.76) at 16 weeks, with sustained but smaller effects at 24 weeks (ES difference = 0.22-0.33). CONCLUSIONS: Next-step studies of this PP-MI program in T2D patients can more rigorously explore the intervention's effects on physical activity and clinical outcomes.