Abstract P197: Factors Contributing to the Success of a Multicomponent Intervention for Blood Pressure Control in Argentina: A Mediation Analysis

Abstract

Introduction: The Hypertension Control Program in Argentina (HCPIA), a cluster-randomized trial of a community health worker-led multicomponent intervention on blood pressure (BP) control in low-income patients in Argentina, previously reported a significant reduction in systolic BP in the intervention compared to the control group over 18 months (6.6 mm Hg net difference; p<0.001). Understanding which elements of a multicomponent intervention are important contributors to its success is critical for future BP control efforts. We conducted a mediation analysis to determine the contributions of seven measured intervention targets to the systolic BP intervention effect. Methods: HCPIA randomized 18 primary healthcare clinics treating uninsured patients to either a multicomponent intervention, consisting of health coaching, home blood pressure monitoring, blood pressure audit and feedback, physician education, and a mobile health intervention, or usual care. A total of 1,357 hypertensive participants completed the trial and are included in the mediation analyses. Changes in seven potential mediators over the 18-month intervention were assessed: medication adherence score, medication adjustments (addition of new medication or dose titration), waist circumference, physical activity, fruit and vegetable consumption, sodium consumption, and alcohol consumption. Generalized estimating equations were used to compare changes in potential mediators between intervention groups. Path analytic models were used to test single-mediator and multiple mediator indirect intervention effects using the Lavaan package in R statistical software. Mediation was considered significant at p<0.10. Results: All potential mediators were significantly improved in the intervention group compared to the control group. Fruit and vegetable consumption, medication adherence, physical activity, and salt consumption are each significant mediators accounting for 4.3, 3.8, 3.3, and 3.2%, respectively, of the intervention effect in single-mediator models. The multiple mediation model explained 15.5% (1.3 mm Hg) of the total intervention effect. Changes in fruit and vegetable consumption and medication adherence remained significant mediators in multiple mediation analysis, responsible for 3.8% and 4.3% of the net reduction in systolic BP, respectively. Other potential mediators did not account for a significant proportion of the intervention effect. Conclusions: Increases in medication adherence and fruit and vegetable consumption were responsible for the largest proportions of the explained intervention effect.