Project Summary/Abstract. Hypertension (high blood pressure) affects 1 in 3 of the over 90 million people
currently enrolled in Medicaid, and is a leading cause of cardiovascular disease and stroke in the U.S. While
multiple effective anti-hypertensive (AH) drugs are widely available in the U.S., they require high (≥80%) life-
long medication adherence to successfully counter cardiovascular morbidity and mortality. Unfortunately, AH
medication adherence is lowest among Medicaid enrollees compared to other insured populations, and
nonadherence is a major barrier to controlled blood pressure. The mechanisms of present bias and habit
strength have been shown to maintain behavior change in several settings, but have not been tested for
maintaining high AH medication adherence. Incentives are effective for improving medication adherence in the
short term, and may reduce present bias by helping people better internalize the future benefits of their actions,
which in turn could maintain AH medication adherence. Therefore, we propose to partner with the widely-used,
commercial Wellth smartphone app, where app users can earn incentives for sending photographic evidence
of their daily pill taking. After withdrawing the Wellth-delivered incentives, we will measure adherence
maintenance. Habitual pill-taking is another key strategy for maintaining behavior change, since habits
performed in response to the same contextual cue for roughly four months are executed with high habit
strength, i.e., are performed with little or no cognitive effort. Existing habit formation interventions have had
difficulty effectively supporting participants, but behavioral economics suggests that providing small incentives
for cueing the new behavior can effectively support habit formation. Thus, this study proposes to also adapt the
Wellth app to reward cued AH pill taking. In a Stage III, 24-month 3-arm real-world efficacy trial, hypertensive
adults with low (<80%) adherence from Arizona Complete Health’s Medicaid plan (n=600; 200 per group) will
be randomly assigned to: 1) ‘Control’ group; 2) ‘Wellth Only’ that will receive daily incentives for submitting a
picture of their AH pill taking; or 3) ‘Wellth+Cue’ that will be asked to describe the cue that will trigger their AH
pill taking and send a second picture of the contextual cue, such as a coffee mug. A 4-month intervention will
be followed by a 20-month post-intervention period to measure maintenance. The Primary Outcomes are mean
AH medication adherence (days covered measured via Medicaid claims) and blood pressure (via at-home
readings at baseline and months 4, 8, 12, and 24). Secondary Outcomes are healthcare utilization (emergency
and inpatient visits) and the costs incurred by Medicaid (via claims data). After the study ends, interviews with
stakeholders and participants (using a positive/negative deviance approach) will ask about potential
implementation barriers to inform intervention refinements and cultural adaptation to prepare for Stage V
implementation research in a future study. If found effective, the study has the potential for immediate scale-up
for maintaining treatment adherence for hypertension and a range of other chronic conditions.
