Introduction: We examined the effectiveness of providing incentives to participants in lifestyle modification programs to improve diabetes-related health indicators: body weight, body mass index (BMI), blood pressure, cholesterol, and hemoglobin A1C (HbA1C). We also examined the potential effect of 4 different incentive domains (ie, type, monetary value, attainment certainty, and schedule) on those indicators.
Methods: We searched Medline, Embase, PsycINFO, and Cochrane Library to identify relevant studies published from January 2008 through August 2021. We used a random-effects model to pool study results and examine between-study heterogeneity by using the I2 statistic and the Cochran Q test. We also conducted moderator analyses by using a mixed-effects model to examine differences between subgroups of incentive domains (eg, incentive type [cash vs other types]).
Results: Our search yielded 10,965 articles, of which 19 randomized controlled trials met our selection criteria. The random-effects model revealed that, relative to the control group, the incentive group had significant reductions in weight (-1.85kg; 95% CI, -2.40 to -1.29; P < .001), BMI (-0.47kg/m2; 95% CI, -0.71 to -0.22; P < .001), and both systolic blood pressure (-2.59 mm HG; 95% CI, -4.98 to -0.20; P = .03) and diastolic blood pressure (-2.62 mm Hg; 95% CI, -4.61 to -0.64; P = .01). A reduction in cholesterol level was noted but was not significant (-2.81 mg/dL; 95% CI, -8.89 to -3.28; P = .37). One study found a significant reduction in hemoglobin A1c (-0.17%; 95% CI, -0.30% to -0.05%; P < .05). The moderator analyses showed that the incentive effect did not vary significantly between the subgroups of the incentive domains, except on weight loss for the attainment certainty domain, suggesting that a variety of incentive subgroups could be equally useful.
Conclusion: Providing incentives in lifestyle modification programs is a promising strategy to decrease weight, BMI, and blood pressure.