Process- and Outcome-Based Financial Incentives to Improve Self-Management and Glycemic Control in People with Type 2 Diabetes in Singapore: A Randomized Controlled Trial

Background Sub-optimally controlled diabetes increases risks for adverse and costly complications. Self-management including glucose monitoring, medication adherence, and exercise are key for optimal glycemic control, yet, poor self-management remains common. Objective The main objective of the Trial to Incentivize Adherence for Diabetes (TRIAD) study was to determine the effectiveness of financial incentives in improving glycemic control among type 2 diabetes patients in Singapore, and to test whether process-based incentives tied to glucose monitoring, medication adherence, and physical activity are more effective than outcome-based incentives tied to achieving normal glucose readings. Methods TRIAD is a randomized, controlled, multi-center superiority trial. A total of 240 participants who had at least one recent glycated hemoglobin (HbA1c) being 8.0% or more and on oral diabetes medication were recruited from two polyclinics. They were block-randomized (blocking factor: current vs. new glucometer users) into the usual care plus (UC +) arm, process-based incentive arm, and outcome-based incentive arm in a 2:3:3 ratio. The primary outcome was the mean change in HbA1c at month 6 and was linearly regressed on binary variables indicating the intervention arms, baseline HbA1c levels, a binary variable indicating titration change, and other baseline characteristics. Results Our findings show that the combined incentive arms trended toward better HbA1c than UC + , but the difference is estimated with great uncertainty (difference − 0.31; 95% confidence interval [CI] − 0.67 to 0.06). Lending credibility to this result, the proportion of participants who reduced their HbA1c is higher in the combined incentive arms relative to UC + (0.18; 95% CI 0.04, 0.31). We found a small improvement in process- relative to outcome-based incentives, but this was again estimated with great uncertainty (difference − 0.05; 95% CI − 0.42 to 0.31). Consistent with this improvement, process-based incentives were more effective at improving weekly medication adherent days (0.64; 95% CI − 0.04 to 1.32), weekly physically active days (1.37; 95% CI 0.60–2.13), and quality of life (0.04; 95% CI 0.0–0.07) than outcome-based incentives. Conclusion This study suggests that both incentive types may be part of a successful self-management strategy. Process-based incentives can improve adherence to intermediary outcomes, while outcome-based incentives focus on glycemic control and are simpler to administer.