Nearly 1 in 2 US adults has hypertension, and it is a leading cause of myocardial infarction, stroke, and death. Despite the importance of hypertension and the widespread availability of medication treatment, only 44% of patients had controlled blood pressures in 2018. This is in part due to the way in which we deliver care, and new strategies are needed to achieve better blood pressure control. Team-based care with medication titration by a non-physician is a promising approach, but the cost and infrastructure required make this option less feasible. An alternative strategy is to have patients self-manage their own hypertension by checking blood pressures and following an algorithm, pre-planned between the patient and primary care doctor, to intensify their medications at home. Despite evidence for the effectiveness and cost- effectiveness of this approach, it has not yet been incorporated into routine care. In this project, we propose to develop an implementation-ready antihypertensive self-titration intervention informed by qualitative interviews and real-world assessments of antihypertensive adherence. The proposed aims are to: (1) explore barriers and facilitators to the implementation of antihypertensive self-titration in routine US primary care; (2) assess adherence to antihypertensive treatments; and (3) develop an implementation-ready antihypertensive self- titration protocol, perform usability testing, and prepare a proposal for a pragmatic, randomized trial to test the intervention’s effectiveness. The overarching goal of the project is to develop an innovative alternative model of hypertension care that has the potential to improve blood pressure control, patient self-efficacy, and disease understanding Dr. Haff is a practicing primary care physician committed to a career in research to improve the prevention and treatment of cardiometabolic disease, and this proposal includes a training plan that will accelerate her career development in the areas of implementation science, qualitative methods, health services research methods, and scientific writing. The mentorship team, led by Niteesh Choudhry, an expert in health services research and implementation science related to cardiometabolic disease, includes well-known experts in preventive cardiology (Paul Ridker, co- mentor), biostatistics (Robert Glynn, co-mentor), and implementation science and qualitative methods (Karen Emmons, co-mentor), and will ensure successful completion of the proposed project and training. By the conclusion of this program, Dr. Haff will be able to independently design, target, and evaluate interventions for cardiometabolic disease. The results of the proposed K23 will be invaluable pilot work for a planned R01-level application.