Secondary analysis of the Game of Stones trial for men with obesity: examining moderator effects and exploratory outcomes

Objective: The objective was to explore whether socioeconomic, health, and behavioral characteristics moderate the effectiveness of a text message intervention with or without financial incentives versus a control group and to examine differences in exploratory outcomes. Methods: This three-group randomized trial including 585 men with obesity compared daily automated behavioral text messages alongside financial incentives, text messages alone, and a waiting list control for 12 months. Moderator analyses examined percentage weight change after 12 months for 9 socioeconomic and 11 health factors. Exploratory outcomes included the following: self-reported physical activity, sedentary behavior, smoking and alcohol behaviors, engagement in 15 weight-management strategies, and weight-management-related confidence. Results: No moderator effects were found by any factors for either comparison versus control. There were no differences across groups for health behaviors. The texts with incentives group had higher levels of engagement in six strategies including weight goals, food changes, and self-weighing and higher levels of confidence compared with the control. Conclusions: The Game of Stones interventions were equally effective across various subgroups based on socioeconomic, health, or well-being status. Texts with financial incentives group participants showed better engagement for some intervention elements. The implementation of Game of Stones is unlikely to increase health inequalities. Future studies should focus on increasing engagement.