Low Sodium Diet Self-Management Intervention in
Project Director – Darlene Welsh, PhD, RN
The purpose of this randomized, controlled study is to test the effects of a theory-based intervention designed to improve dietary sodium restriction self-management in chronic heart failure (HF) patients. A secondary purpose is to test the impact of the intervention on patient attitudes, subjective norm and perceived behavioral control which are the constructs of the Theory of Planned Behavior (TPB). Heart failure is the most rapidly growing cardiovascular disorder in the United States and the leading cause of hospital admissions for Medicare patients. The most common proximate cause of HF hospitalizations is volume overload, in most cases, attributed to failure to self-manage a low sodium diet. Explicit teaching regarding dietary sodium restriction is essential to adherence in those with chronic HF. No studies have been performed isolating the effect of a theory based intervention on adherence to the recommended 2 gram sodium diet in HF patients.
The specific aims of this study are to test the impact of a theory-based self-management intervention designed to improve adherence to the low sodium diet on: 1) hospitalization and time alive out of hospital; 2) adherence to a low sodium diet; 3) quality of life; 4) indicators of the constructs of the Theory of Planned Behavior; 5) symptoms; 6)B-type natriuretic peptide (BNP) levels, and, 7) heart rate variability (HRV). Fifty patients with chronic HF will be recruited into this pilot study and randomly assigned to either a control or intervention group. Inclusion criteria are: (1) a confirmed diagnosis of HF due to left ventricular systolic dysfunction or with preserved systolic function; (2) New York Heart Association Class II - IV; (3) no cognitive impairments limiting the ability to complete an interview; (4) residence outside of an extended care facility and within 60 miles of the University of Kentucky; (5) 21 years of age or older; 6) hospitalization for HF treatment 6 months prior to study entry, and, 7) English speaking. Data will be collected at baseline, 6 weeks and at 6 months. The control group will receive usual care; the intervention group will receive a customized low-sodium diet self-management intervention that focuses on providing knowledge and other tools for effective dietary self-management. The intervention will include instruction on dietary sodium restriction that is tailored to meet specific patient learning needs, overcome individual barriers to adherence, and involve significant others.
The log-rank test will be used to compare time to heart failure hospitalization between the intervention and control groups. Cox proportional hazards regression also will be used to assess predictor of this endpoint. Kaplan-Meier plots will be used to graphically depict group differences in readmission-free survival. Repeated measures analysis of variance (ANOVA) will be used to compare the two groups on adherence, quality of life, indicators of the constructs of the TPB, symptoms, BNP, and heart rate variability. Results from this study will demonstrate the potential of a focused, single component intervention to improve outcomes in patients with HF. In addition, this study will provide essential pilot data for a planned R01 submission in 2010.