Cost-effectiveness of habit-based advice for weight control versus usual care in general practice in the Ten Top Tips (10TT) trial: economic evaluation based on a randomised controlled trial

OBJECTIVE: Ten Top Tips (10TT) is a primary care-led behavioural intervention which aims to help adults reduce and manage their weight by following 10 weight loss tips. The intervention promotes habit formation to encourage long-term behavioural changes. The aim of this study was to estimate the cost-effectiveness of 10TT in general practice from the perspective of the UK National Health Service. DESIGN: An economic evaluation was conducted alongside an individually randomised controlled trial. SETTING: 14 general practitioner practices in England. PARTICIPANTS: All patients were aged ≥18 years, with body mass index ≥30 kg/m2. A total of 537 patients were recruited; 270 received the usual care offered by their practices and 267 received the 10TT intervention. OUTCOMES MEASURES: Health service use and quality-adjusted life years (QALYs) were measured over 2 years. Analysis was conducted in terms of incremental net monetary benefits (NMBs), using non-parametric bootstrapping and multiple imputation. RESULTS: Over a 2-year time horizon, the mean costs and QALYs per patient in the 10TT group were £1889 (95% CI £1522 to £2566) and 1.51 (95% CI 1.44 to 1.58). The mean costs and QALYs for usual care were £1925 (95% CI £1599 to £2251) and 1.51 (95% CI 1.45 to 1.57), respectively. This generated a mean cost difference of -£36 (95% CI -£512 to £441) and a mean QALY difference of 0.001 (95% CI -0.080 to 0.082). The incremental NMB for 10TT versus usual care was £49 (95% CI -£1709 to £1800) at a maximum willingness to pay for a QALY of £20 000. 10TT had a 52% probability of being cost-effective at this threshold. CONCLUSIONS: Costs and QALYs for 10TT were not significantly different from usual care and therefore 10TT is as cost-effective as usual care. There was no evidence to recommend nor advice against offering 10TT to obese patients in general practices based on cost-effectiveness considerations. TRIAL REGISTRATION NUMBER: ISRCTN16347068; Post-results.