The roles of motivational interviewing and self-efficacy on outcomes and cost-effectiveness of a community-based exercise intervention for inactive middle-older aged adults.

Abstract

Increasing physical activity (PA) among inactive middle-older aged adults in rural communities is challenging. This study investigates the efficacy of a PA intervention supporting inactive adults in rural/semirural communities. Inactive participants enrolled on either a single signposting session (n=427) or a multisession pathway combining signposting with motivational interviewing (MI; n=478). Pre-post outcomes data assessed activity levels (International Physical Activity Questionnaire-Short Form; Single Item Sport England Measure), self-efficacy (New General Self-Efficacy scale [NGSE]) and well-being (five-item World Health Organization Well-Being Index [WHO-5]). Measures were repeated at longitudinal time points (26, 52weeks) for the MI pathway. Outcomes were contrasted with results from an unmatched comparison group receiving treatment as usual (TAU). Cost-utility (quality-adjusted life years [QALY]-incremental cost-effectiveness ratio) and return on investment (NHS-ROI; QALY-ROI) were estimated for short (5years), medium (10years) and long (25years) time horizons. Both pathways significantly increased participants' PA. The MI pathway resulted in significantly greater increases in PA than signposting-only and TAU. Improvements in psychological outcomes (NGSE; WHO-5) were significantly greater in the MI pathway than TAU. Longitudinal results indicated MI pathway participants sustained increases in light-intensity PA at 52weeks (p<0.001; =0.16). Regression analyses found baseline self-efficacy predicted increased PA at 52weeks, while baseline well-being did not. The relationship between self-efficacy and PA increased successively across time points. However, magnitude of participants' increased self-efficacy did not predict PA at any time point. Both pathways were cost-effective and cost -saving for participants aged ≥61years from the short time horizon, with the MI pathway having greater ROI estimates. Overall, MI increased efficacy of a signposting PA intervention and was cost-saving for older adults.