Long-term Effects of Text Messages with Financial Incentives for Men with Obesity: Two-year Follow-up of the Game of Stones trial

Abstract

Objectives: To compare the difference in percentage weight change at 24 months following a 12-month text messaging with financial incentive intervention compared to a waiting list control group, and to compare the text messaging alone group to the control group. Design: Assessor-blinded three-arm randomised clinical trial. Setting: Three disadvantaged communities from the UK. Participants: 585 men with body mass index (BMI) of ≥30kg/m2 enrolled between July 2021 and May 2022, of which 377 participants (64%) completed 24 months’ follow-up. Interventions: 12 months of daily behavioural text messages combined with financial incentives; 12 months of the same text messages alone; or waiting for 12 months followed by receipt of the first 3 months (months 12-15) of text messages (control). Main outcome measures: Within-participant change from baseline weight. Results: At 24 months, the mean percent weight change (standard deviation) was −3.9% (6.9%) for the text messaging with financial incentives group, −2.6% (6.8%) for the text messaging alone group, and −2.2% (6.8%) for the control group. Compared with the control group, the mean percent weight change was not significantly greater in the text messaging with financial incentives group (mean difference, −1.0%; 97.5% CI, −2.6 to 0.6; P = .22) or the text messaging alone group (mean difference, −0.0%; 97.5% CI, −1.6 to 1.5; P = .95).At least 5% weight loss at 24 months was achieved by 52 (40%) participants in the text messaging with financial incentives group; 32 (28%) in the text messaging alone group and 43 (32%) in the control group. Conclusions: A scalable, low-cost text message with financial incentives intervention supported clinically relevant maintenance of weight loss 12 months after the intervention ceased, including those from disadvantaged backgrounds.