RESUMO
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.
