UC Davis

Background: Heart failure (HF) management strategies include pharmacological, device, and lifestyle interventions. Advances in HF management may delay disease progression while maintaining and improving quality of life. Systematic evaluation of lifestyle interventions and their effects are important for controlling HF and empowering patients to be active in their health and well-being. Current nutrition recommendations for HF management include sodium and fluid restrictions. These restrictions, however, lack supporting evidence outside of inpatient settings and may promote inadequate dietary intake and impaired nutrition status. Emerging data suggest efficacy of the comprehensive Dietary Approaches to Stop Hypertension (DASH) diet for HF management in controlled feeding studies, but pragmatic evidence is needed evaluating the DASH diet under real-world conditions. Additionally, nutrition research lacks formal evaluation of effectiveness and implementation of new interventions that could enhance evidence-based nutrition care. The research presented in this dissertation evaluates the implementation and effectiveness of the DASH diet for outpatient HF management using implementation, disease management, and patient-centered outcomes. Methods: A pilot single-center prospective hybrid type 1 effectiveness-implementation pragmatic clinical trial was used to evaluate the implementation and effectiveness of a DASH diet nutrition education intervention. Patients were recruited from February 2022 through September 2023 from the advanced heart failure outpatient program in a major academic health center. The intervention was delivered over 6 months through four visits by a registered dietitian who personalized medical nutrition therapy for individual patients based on patient knowledge and understanding, cultural practices, and food preferences. Motivational interviewing principles were incorporated into nutrition counseling, including expressing empathy, developing a discrepancy, and supporting self-efficacy. Qualitative data and the PRISM (Practical, Robust, Implementation, and Sustainability Model) framework were used for implementation evaluation based on cardiology clinic staff and provider attitudes; intervention barriers, facilitators, adaptations, and modifications; and interviews capturing patients’ experience in the intervention. Effectiveness outcomes included dietary intake and DASH diet scores based on 3-day food records, HF-related biomarkers (e.g., vitals, weight, biochemical laboratory values), Eating Habits Confidence Questionnaire diet self-efficacy scores, and Kansas City Cardiomyopathy Questionnaire patient perceived health status scores. Results: Twenty-six patients (58% women; 73% white; 50% retired) ranging in age from 34-85 y completed the intervention. Staff and provider attitudes were neutral to intervention implementation, but these interest-holders were influential in clinic implementation. Context-specific factors affected all aspects of intervention implementation. Reactive modifications were made to improve intervention implementation and delivery in response to encountered challenges. Despite implementation challenges, patients expressed positive experiences participating in the study, as well as improvements in self-reported quality of life and confidence making diet changes. The intervention did not improve HF-related biomarkers, but patient perceived health status improved significantly. Patients consumed more dietary fiber after the first three months of the intervention and many biomarkers and dietary data trended towards improvement. Conclusion: Despite limited biomarker and diet changes, patient feedback regarding the intervention was positive and patient perceived health status score improvements reached both statistical and clinical significance. These patient-centered outcomes will support intervention adaptations to optimize the DASH diet nutrition education intervention and delivery, as well as subsequent hybrid type effectiveness-implementation studies evaluating the real-world impact of nutrition interventions for HF management and practical clinical implementation strategies in outpatient cardiology nutrition care.