Telephone-Based Motivational Interviewing for People with Metabolic Syndrome: A Mixed Methods Feasibility Study

BACKGROUND AND AIMS: Telephone-based motivational interviewing (MI) may be a low-cost, scalable intervention to support behavior change and improve outcomes for people with metabolic syndrome. However, robust trials are required to enable service providers to make informed choices about investment in these programs. In preparation for such a trial, feasibility and cost-effectiveness of potential interventions need to be established. Therefore, this study aimed to determine the feasibility of a multicomponent intervention incorporating physiotherapist-delivered, telephone-based MI for adults with metabolic syndrome and to estimate effects on cardiometabolic risk factors, behavior change, quality of life, and cost-effectiveness. METHODS: Single-group, mixed-methods feasibility study. Adults with metabolic syndrome received brief guideline-based education plus telephone MI (8 weekly sessions and two boosters). Feasibility according to Bowen's framework was assessed via demand (recruitment), acceptability (qualitative), implementation (session completion, intervention fidelity [MITI-4]), and practicality (intervention costs and adverse events). Secondary outcomes (efficacy) were measured at baseline and 6 months and analyzed using within-participant change. Costs and exploratory cost-effectiveness were described. RESULTS: Twenty-seven out of 58 eligible participants were recruited (47%). Twenty-four commenced and 23 completed all 10 MI sessions (98% attendance). MITI-4 coding indicated competent MI delivery. One fall without injury and one withdrawal were reported. At 6 months, steps/day increased (MD 974; 95% CI 102-1847) and waist circumference decreased (-2.2 cm; 95% CI -4.3 to -0.1); quality of life and diet adherence also improved. Mean intervention cost was AUD515/participant; cost-effectiveness outcomes were uncertain due to variability. CONCLUSIONS: Telephone MI for adults with metabolic syndrome was feasible and implemented with fidelity, with promising behavioral and cardiometabolic improvements observed. A randomized trial with longer follow-up and robust economic evaluation is warranted.