Protocol for a Type 3 hybrid effectiveness-implementation cluster randomized trial to evaluate multi-ethnic, multilevel strategies and community engagement to eliminate hypertension disparities in Los Angeles County.

BACKGROUND: In the U.S., racial and ethnic disparities in hypertension control contribute to disparities in cardiovascular mortality. Evidence-based practices (EBPs) for improving hypertension control have not been consistently applied across patient subgroups, especially in safety-net settings, contributing to observed disparities. The Los Angeles County Department of Health Services serves racially and ethnically diverse, low-income patients with hypertension and represents a valuable setting for research to reduce disparities. We designed a hybrid Type 3 effectiveness-implementation study using a three-arm, crossover randomized controlled trial to compare the effects of patient- and provider-focused strategies and usual implementation strategy on key implementation and clinical outcomes.

METHODS: We will enroll 27 primary care clinics. Patient-focused implementation strategies aim to increase patient access to culturally and linguistically tailored educational materials on hypertension and improve patient engagement in hypertension care. Provider-focused strategies include training in culturally tailored hypertension care and activities to strengthen clinic workflows for home blood pressure monitoring, medication titration, referral to nurse-directed blood pressure clinics, and social needs screening and referral. Implementation facilitators provide support for these EBPs. The primary implementation outcome is provider EBP adoption clustered at the clinic level, based on a scoring system using medical records, clinic observation, and webinar participation. The primary health-related outcome is the proportion of patients in a clinic with controlled hypertension by race and ethnicity. We will use the constrained generalized Poisson mixed-effects model to compare changes in event rate of provider EBP adoption between usual implementation strategy and either provider- or patient-focused strategies. We will use constrained logistic mixed-effects models to assess the effect on change in blood pressure control. We will record implementation progress using the Stages of Implementation Completion tool and identify costs and resource use using the Cost of Implementing New Strategies tool.

DISCUSSION: Our study contributes to the implementation science literature on cardiovascular health equity by examining alternative implementation strategies to increase use of culturally and linguistically tailored hypertension EBPs and social needs screening and intervention. Findings from our study will build evidence for implementation of hypertension EBPs in safety-net and other health systems serving racial and ethnic minority patients.

TRIAL REGISTRATION: Clinicaltrials.gov NCT06359691, registered April 10, 2024.