The investigators will pilot test a hypertension self-management intervention for feasibility and acceptability. This is a pilot study to gain experience in enrolling and retaining patients from the identified population and collecting outcome variables. Study cohort: The investigators will enroll adults (age ≥18) with uncontrolled hypertension, identified from the electronic health record problem list and an average systolic blood pressure (BP) of 150-199 or diastolic of 95-119 mmHg at 2 ambulatory visits, 1 of which is within 6 months of study entry. These BP criteria ensure enrollment of individuals who warrant improved BP control. In this feasibility trial, the research aim is to explore trial design, participant acceptability of the intervention and outcome measures, and to generate data to inform the design of a future RCT. We will employ a validated approach to determine feasibility (e.g., acceptability, satisfaction, and practicality).

All secondary measures will be collected at baseline, 30 days, and end of intervention (90 days). These outcomes are pilot measures that will be used in a subsequent full-scale efficacy trial of the intervention.

Study protocol. Duration = 90 days. Allocation will use a randomly permuted block design. The investigators will provide smartphones and cellular subscriptions to all participants, as in their prior studies of cardiovascular disease mobile health interventions. This obviates the need for smartphone ownership or internet access. Participants randomized to the intervention group will receive the smartphone with the intervention program preloaded in addition to a BP monitor. The active comparison group will receive a smartphone with a basic health information application preloaded and a BP monitor. After recruitment, participants will receive a confirmatory interview, informed consent, and baseline device training via telephone, delivered by an experienced research assistant. Participants will be encouraged to complete 1 morning BP reading daily, irrespective of study arm, however, only the intervention group will receive reminders from the mHealth coaching intervention to check BP daily. BP readings are automatically uploaded via Bluetooth to a centralized, secure platform to be accessible to the study PI. Participants will receive $20 for the baseline telephone visit and $40 at study completion. As in the groups' prior RCTs, the final payment requires return of the smartphone.

Sample Size Justification and Recruitment. Investigators will focus on feasibility outcomes among 40 patients, following examples in the literature and guidelines for feasibility studies, which recommend against estimating preliminary efficacy or standard errors using pilot data. Nevertheless, with 40 participants, the investigators will have the ability to calculate point estimates and 95% confidence intervals with a margin of error of 0.22. The cohort of 40 will be reasonably recruited in the allotted timeframe. Culturally sensitive recruitment strategies will be employed to ensure participant diversity. In addition, participants will be recruited from outpatient clinics via HIPAA-compliant, IRB approved protocols. The investigators will deploy IRB-approved virtual recruitment strategies previously developed by the study's PI with study brochure and opt-out postcard; electronic health record screening for eligibility; telephone-based confirmatory interview, and informed consent.

Statistical Analysis. Descriptive data, such as means, standard deviations, and sample proportions, will be reported for all participants and by study arm. Data with non-normal distributions will be transformed, as needed. The primary focus will be on feasibility and acceptability as defined above. Primary outcomes will be assessed with point estimates and 95% CIs. Any between-arm differences will be examined using χ2 tests or 2-sided Fisher's exact test for categorical variables, and 2-tailed t tests for continuous variables. Continuous secondary outcomes (locus of control, resilience, BP) will be analyzed using ANCOVA comparing 90-day outcomes between arms after adjusting for baseline BP. The proportion of participants who are normotensive will be analyzed by logistic regression as a function of study arm.