This project audited attendance and weight loss in a primary care/commercial weight management partnership scheme in patients who participated over 6 months. 4754 adult patients (575 men, 4179 women) were referred to Slimming World for 24 weekly sessions. Data were analysed using individual weekly weight records. Mean (standard deviation, SD) body mass index (BMI) change was -3.3 kg m(-2) (2.2), weight change -8.9 kg (6.0), percent weight change -8.6% (5.3) and number of sessions attended 21.3 (3.2) of 24. For patients attending at least 20 of 24 sessions (n = 3626 or 76.3%), mean (SD) BMI change was -3.6 kg m(-2) (2.2), weight change -9.6 kg (6.1), percent weight change -9.3% (5.3). Weight loss was greater in men than women (P < 0.001). 74.5% of all patients enrolled, and 79.3% of patients attending 20 or more sessions achieved at least 5% weight loss. 37.3% of the whole population lost ≥10% of their weight. Weight gain was prevented in 96.3% of all patients referred. Referral to a commercial organization for community-based lifestyle intervention is a practical option for longer-term National Health Service weight management strategies.

BackgroundIt is not clear if behaviour change programmes are more or less effective for weight management in people with high BMIs than for those who are moderately overweight. An earlier service evaluation reported on the rate and extent of weight loss in a primary care/commercial weight management organisation partnership scheme, in 34,271 patients were referred by their health care professionals to a UK commercial weight management organisation, Slimming World for 12 weekly sessions. This project updated that service evaluation by examining weight loss outcomes as a function of initial BMI in the same 34,271 patients.FindingsPatients referred to the scheme (n = 34,271) were categorised by BMI groups <30 kg/m2, 30-34.9 kg/m2, 35-39.9 kg/m2 and to ≥ 40 kg/m2. Mean weight losses after 12 weekly sessions were 2.9, 3.6, 4.1, and 4.8 kg for each BMI category respectively. Regression analysis showed that after adjusting for age and gender, relative to the <30 kg/m2 group, absolute weight losses were 0.8, 1.4 and 2.4 kg more for the 30-34.9 kg/m2, 35-39.9 kg/m2 and to ≥ 40 kg/m2 groups, respectively (all p<0.001). Percent weight loss was similar in each BMI category: 3.7%, 4.0%, 4.0% and 3.9%, respectively (p<0.001).ConclusionsThis service evaluation demonstrates that 12 week referral to a commercial organisation is as effective for people with high BMIs as for those who are moderately overweight.