Lay Advisor Interventions for Hypertension Outcomes: A Systematic Review, Meta-Analysis, and RE-AIM Evaluation Provisionally Accepted

Sonal Patil^{1, 2, 3*} Vishwa Bhayani⁴ Yilin Yoshida⁵ Leila Bushweller⁶ Eno-Obong Udoh⁶ Todorov Irina⁷ Robert SAper⁷ Kurt C. Stange⁸ Shari Bolen¹

• ¹Population Health Research Institute, MetroHealth Medical Center, United States
• ²Center for Reducing Health Disparities, Population Health Research Institute, MetroHealth Medical Center, United States
• ³Case Medical Center, School of Medicine, Case Western Reserve University, United States
• ⁴University of Missouri, United States
• ⁵Tulane University, United States
• ⁶Cleveland Clinic Lerner College of Medicine, School of Medicine, Case Western Reserve University, United States
• ⁷Cleveland Clinic, United States
• ⁸Center for Community Health Integration, School of Medicine, Case Western Reserve University, United States

Introduction: Lay advisor interventions improve hypertension outcomes; however, the added benefits and relevant factors for their widespread implementation into health systems are unknown. We performed a systematic review to: 1) summarize the benefits of adding lay advisors to interventions on hypertension outcomes, and 2) summarize factors associated with successful implementation in health systems using the Reach, Effectiveness, Adoption, Implementation, Maintenance (RE-AIM) framework. Methods: We systematically searched several databases, including Ovid MEDLINE, CINAHL, PsycINFO from January 1981 to May 2023. All study designs of interventions delivered solely by lay advisors for adults with hypertension were eligible. If both arms received the lay advisor intervention, the study arm with lower intensity was assigned as the low-intensity intervention. Results: We included 41 articles, of which 22 were RCTs, from 7267 screened citations. Studies predominantly included socially disadvantaged populations. Meta-analysis (9 RCTs; n=4220) of eligible lay advisor interventions reporting outcomes showed improved systolic blood pressure (BP) [-3.72 mm Hg (CI -6.1 to -1.3; I 2 88%)], and diastolic BP [-1.7 mm Hg (CI -1 to -0.9; I 2 7%)] compared to control group. Pooled effect from six RCTs (n=3277) comparing high-intensity with low-intensity lay advisor interventions showed improved systolic BP of -3.6 mm Hg (CI -6.7 to -0.5; I 2 82.7%) and improved diastolic BP of -2.1 mm Hg (CI -3.7 to -0.4; I 2 70.9%) with high-intensity interventions. No significant difference in pooled odds of hypertension control was noted between lay advisor intervention and control groups, or between high-intensity and low- intensity intervention groups.. Most studies used multicomponent interventions with no stepped care elements or reporting of efficacious components. Indicators of external validity (adoption, implementation, maintenance) were infrequently reported. Discussion: Lay advisor interventions improve hypertension outcomes, with high intensity interventions having a greater impact. Further studies need to identify successful intervention and implementation factors of multicomponent interventions for stepped upscaling within healthcare system settings as well as factors used to help sustain interventions.