Behavioral Economics and Medication Adherence for Hypertension

Background: Nonadherence to antihypertensive medications is common. Mobile health (mHealth) based behavioral economic interventions may improve adherence, but remain largely untested, especially in vulnerable populations. Objective: To test whether an mHealth incentive lottery would lower systolic blood pressure (SBP) and improve adherence. Methods: BETTER-BP was a randomized trial conducted in 3 safety-net clinics in NYC. Eligible participants were adults with hypertension prescribed at least one antihypertensive medication, with SBP >140 mmHg, and poor self-reported adherence. In the intervention arm, an incentive lottery was administered via SMS messaging. All participants received passive adherence monitoring. The intervention lasted 6 months, with continued monitoring until 12 months. The primary clinical endpoint was change in SBP at 6 months. The primary process endpoint was adequate antihypertensive medication adherence (≥80% days adherent) from baseline to 6 months. Results: 400 participants (265 intervention:135 control) were enrolled with median age 57 years, 60.5% women, 61.5% Hispanic, and 20.3% non-Hispanic Black. Over 70% had Medicaid or no insurance. At 6 months, intervention arm participants were twice as likely to achieve adequate adherence (71% vs. 34%, adjusted risk ratio [ARR] = 2.04, 95% CI 1.58, 2.63), but there was no significant change in mean SBP (−6.7 mmHg intervention vs. −5.8 mmHg control, P=0.62). From 6 to 12 months, adherence was similar (31% intervention vs. 26% control, ARR = 1.17, 95% CI 0.83, 1.65). Conclusions: In a diverse safety-net population, the BETTER-BP intervention doubled the rate of adequate antihypertensive medication adherence but did not reduce SBP at 6 months.