Motivational interviewing for modifying diabetes risk: a randomised controlled trial

BACKGROUND: Around 10-15% of adults aged over 40 years have pre-diabetes, which carries a high risk of progression to type 2 diabetes. Intensive lifestyle intervention reduces progression by as much as 58%. However, the cost and personnel requirements of these interventions are major obstacles to delivery in NHS primary care. AIM: To assess the effectiveness of a low-cost intervention, delivered in primary care by non-NHS staff, to reduce the risk of diabetes through weight loss and physical activity. DESIGN OF STUDY: Pragmatic single-blind randomised controlled trial with researchers and statistician blinded to group allocation. SETTING: UK primary care. METHOD: One-hundred and forty-one participants with a body mass index of 28 kg/m2 or more, but without diabetes or heart disease, received either information leaflets or individual behavioural counselling using motivational interviewing techniques. The intervention was delivered by five counsellors recruited from the local community. The primary outcomes were the proportions of participants meeting predefined targets for weight loss (5%) and moderate physical activity (150 minutes/week) after 6 months. RESULTS: Using intention-to-treat analysis, more people in the intervention group achieved the weight-loss target (24% versus 7% for controls; odds ratio OR=3.96; 95% confidence interval Cl=1.4 to 11.4; number needed to treat NNT=6.1 (95% Cl=4 to 21). The proportion achieving the physical activity target did not increase significantly (38% versus 28% for controls; OR=1.6; 95% Cl=0.7 to 3.8). CONCLUSION: Short-term weight loss, at a level which, if sustained, is clinically meaningful for reducing diabetes risk, is achievable in primary care, without excessive use of NHS monetary or personnel resources.