Community intervention to reduce cardiovascular disease in Chicago (CIRCL-Chicago): protocol for a type 3 hybrid effectiveness-implementation study using a parallel cluster-randomized trial design

BACKGROUND: Hypertension affects nearly half of adults in the U.S., with African American and Black (AA/B) adults experiencing some of the highest rates domestically and globally. Despite improvements in blood pressure control in the general population, rates of control among AA/B adults have stagnated, contributing to significant health disparities in the prevalence of hypertension and its long-term health impacts. Systemic barriers, including poverty and historically earned distrust in healthcare, hinder patient and clinician adherence to best practices for hypertension management. Community-based interventions, particularly those involving faith-based organizations, show promise in improving blood pressure control among AA/B adults. METHODS: The CIRCL-Chicago Implementation Research Center will test the effectiveness of a community-adapted hypertension control program, a "bundled" intervention developed by and tested in the Kaiser Permanente system, in South Side Chicago community health centers. A key partner for this trial, the Total Resource Community Development Organization, isa faith-based community outreach hub networked with faith-based organizations throughout Chicago's South Side community. The study employs a type 3 hybrid effectiveness-implementation approach with a parallel cluster-randomized trial. Sixteen clinics will be randomized to implement a community-adapted Kaiser bundle with or without practice facilitation. We will recruit adults who live, work, or practice their faith in Chicago's South Side community to populate a community-based hypertension registry (target n = 5,760 participants). The primary implementation outcome is the reach of the intervention, measured by the proportion of eligible patients in the registry who receive the adapted Kaiser bundle. Secondary outcomes include blood pressure control rates, assessed at 12 months post-enrollment. The study will use community-engaged adaptation, practice facilitation, and education and training strategies to support implementation. DISCUSSION: The CIRCL-Chicago study aims to address cardiovascular health disparities by integrating clinical and community-based approaches to hypertension management. By leveraging trusted community settings and engaging local partners, the study seeks to enhance the reach and effectiveness of evidence-based hypertension interventions. The findings could inform scalable models for hypertension control in diverse urban communities, potentially reducing health disparities for AA/B adults. TRIAL REGISTRATION: Clinicaltrials.gov NCT04755153 on 24 August 2023, https://www.centerwatch.com/clinical-trials/listings/NCT04755153/community-intervention-to-reduce-cardiovascular-disease-in-chicago.