A multi-centre randomised controlled trial comparing the effectiveness of enhanced motivational interviewing with usual care for reducing cardiovascular risk

ABSTRACT Aim: To compare in a RCT the effectiveness and cost-effectiveness of two formats of a motivational interviewing manualised intervention, group and individual, with usual care, in reducing weight and increasing physical activity in people at high risk of cardiovascular disease over a 24 months follow up. Methods: This is a 3 parallel arm multi-centre RCT based in the South London Health Innovation and Education Cluster (HIEC), which includes 11 clinical commissioning groups (CCGs) across South London. Randomisation is stratified by GP borough. Following consent, participants are randomized to usual care, usual care and group motivational interviewing, or usual care and individual motivational interviewing. Participants: Adults aged 40-74 years who screen positive for high CVD risk (Qrisk2 score >20%) and are not known to have cardiovascular disease or to be on the diabetes, kidney, atrial fibrillation or stroke register. Measures: Collected at baseline, 12 and 24 months. Primary outcomes are differences in weight (kilograms) and in physical activity (number of timed steps) between arms at 24 months (interim outcome at 12 months). Secondary outcomes are differences in lipids, blood pressure, HbA1c, CVD risk and in smoking status at 24 months. The EQ-5D will be used to generate quality-adjusted life years. Data analysis: Intention-to-treat statistical analyses will be conducted using STATA 11. Linear mixed models will compare the three treatment groups on all outcome measures at 12 and 24 months accounting for baseline covariates and stratification. Costs and outcomes (primary and QALYs) will be combined in a cost-effectiveness analysis with uncertainty addressed using cost-effectiveness planes and cost-effectiveness acceptability curves. Process Evaluation: We will conduct qualitative and quantitative analyses to identify which components of the intervention were used more often, which were preferred by the healthy lifestyle facilitators and participants and which appeared to be most effective. We will also measure the level of adherence to the intervention by the healthy lifestyle facilitators adapting recent frameworks for measuring competencies to behaviour change techniques. SUMMARY The study is a 3 parallel arm multi-centre RCT for people at high risk for cardiovascular disease (CVD). It will take place within the South London HIEC, which includes 11 clinical commissioning groups across South London, constitutes a population of approximately 3 million residents and is representative of the UK’s highly diverse social, economic and ethnic communities. After informed consent, participants will be randomized to usual care (group 1), usual care and group motivational interviewing (group 2) or usual care and individual motivational interviewing (group 3). *Participants in group 1 will receive usual care from their GPs participating in the study; GP's will be expected to follow their local care pathway for those who have a CVD risk score >20%. *Participants in group 2 will receive usual care and group motivational interviewing. The programme will consist of 10 sessions lasting 120 minutes each over 12 months delivered by healthy lifestyle facilitators trained in behaviour change techniques. The intensive phase will be 6 weekly sessions. The maintenance phase will be 4 sessions delivered at 3, 6, 9 and 12 months. The contents will focus on early setting of goals and of maintenance techniques using the group environment to facilitate change. We will include visual aids, patient testimonials, behavioural surveys and e-technology tools to enhance self-monitoring and feedback of healthier behaviours (mobile texts, social networking sites), pedometers. *Participants in group 3 will receive usual care and individual motivational interviewing. This will have the same components as group 2 but delivered individually. Sessions will last 40 minutes. Intention-to-treat statistical analyses will be conducted u