Phenotypes of Hypertensive Ambulatory Blood Pressure Patterns: Design and Rationale of the ECHORN Hypertension Study.

Objective: To describe the rationale and design of a prospective study of ambulatory blood pressure measurement (ABPM) combined with measurement of contextual factors to identify hypertensive phenotypes in a Caribbean population with high rates of HTN and cardiovascular disease. Design: Prospective, multi-center sub-study. Setting: Eastern Caribbean Health Outcomes Research Network Cohort (ECHORN) Study, with study sites in Puerto Rico, the US Virgin Islands, Trinidad and Tobago, and Barbados. Participants: Community-residing adults without a diagnosis of HTN and not taking antihypertensive medication. Intervention: Ambulatory BP patterns are assessed using 24-hour ABPM. Contextual factors are assessed with: ecological momentary assessment (7-item survey of experiences, exposures and responses associated with daytime BP measurements); actigraphy (capturing physical activity and sleep quality); and self-report surveys (assessing physical and social health, environmental and social stressors and supports). Main Outcome Measures: Phenotypes of contextual factors associated with hypertensive BP patterns (sustained HTN, masked HTN, and nocturnal non-dipping). Methods and Results: This study will enroll 500 participants; assessments of blood pressure and contextual factors will be conducted during Waves 2 and 3 of the ECHORN parent study, occurring 2 years apart. In Wave 2, we will assess the association between contextual factors and ABPM patterns. Using advanced analytic clustering methods, we will identify phenotypes of contextual factors associated with hypertensive ABPM patterns. We will then test the stability of these phenotypes and their ability to predict change in ABPM patterns between Waves 2 and 3. Conclusions: Assessment of ABPM, and the contextual factors influencing ABPM, can identify unique phenotypes of HTN, which can then be used to develop more precision-based approaches to the prevention, detection and treatment of HTN in high-risk populations.