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

ObjectivesTo 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. DesignAssessor-blinded three-arm randomised clinical trial. SettingThree disadvantaged communities from the UK. Participants585 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. Interventions12 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 measuresWithin-participant change from baseline weight. ResultsAt 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. ConclusionsA 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. What is already known on this topicO_LIMen, particularly those in lower socio-economic groups, engage less frequently in existing weight loss interventions and services, and might benefit from gender-sensitized interventions. C_LIO_LIThe Game of Stones trial showed that a 12-month intervention consisting of text messaging with endowment financial incentives resulted in statistically significant weight loss in men with obesity compared with control. C_LI What this study addsO_LIAt 24 months, participants receiving 12 months of behavioural text messages with financial incentives displayed continued weight loss which is likely to be clinically important for some men. C_LIO_LIThis digital, scalable, low risk text messaging with financial incentives intervention, with low participant and staff burden, shows promise for longer-term weight maintenance in men, including those living in the most deprived areas. C_LI