A Service Evaluation of More Than 27 000 Adults Referred to a Community Weight Management Program: 24-Month Outcomes

Obesity has a significant impact on healthcare resources with limited accessible support available through the NHS. This service evaluation determines 24-month efficacy of referral to an open-group behavioral program by BMI category and socioeconomic status.

This retrospective, longitudinal study examined weight outcomes of adults living in England referred by healthcare professionals to Slimming World during 2016 who recorded at least 1 weight change. Primary outcome was % weight change at 3, 6, 12, and 24 months. Socioeconomic status was measured using the Index of Multiple Deprivation (IMD). Data from a post-referral questionnaire investigated self-reported changes in dietary and activity behaviors.

Twenty-seven thousand five hundred sixty (15.6% male) records were analyzed. Mean (SD) age and BMI on joining were 48.6 (14.80) years and 37.1 (6.31) kg/m²; 91.7% had a BMI > 30 kg/m². Mean (SD) % weight change was -5.6 (3.79), -7.1 (5.71), -7.5 (6.88), and -7.3 (6.88) at 3, 6, 12, and 24-months, respectively. At 24- months, differences in weight loss between BMI category were significant, ranging from 0.29% (35-<40 vs 40+) to 1.33% (25-<30 vs 40+). For IMD quintile only comparisons against Q1 and Q2 were significant, ranging between 0.36% (Q2 vs Q3) to 0.94% (Q1 vs Q5). Five thousand eight hundred sixty-two (21.2%) completed the post-referral questionnaire. There were no BMI category effects on dietary behaviors but changes in physical activity behaviors were lower within the higher categories albeit effect sizes were small (all ges < 0.001). IMD quintile influenced changes for sugary drinks, watching TV and avoiding moderate activity although effect sizes were small (all ges < 0.01).

Following 12-week referral to a commercial weight management organization, a mean weight loss of over 7% was reported at 24-months. Adults with higher BMIs and a greater level of deprivation can benefit from the practical support offered as part of the referral, supporting weight loss and weight loss maintenance albeit with some inequality.