Self-reported adherence to a low-sodium diet and health outcomes in patients with heart failure

Background: Most clinicians rely on patients' self-report of following a low-sodium diet to determine adherence of patients with heart failure (HF). Whether self-reported adherence to a low-sodium diet is associated with cardiac event-free survival is unclear. Purposes: To determine (1) whether self-reported is concordant with adherence to a low-sodium diet measured by food diaries and 24-hour urinary sodium excretion and (2) whether self-reported adherence to a low-sodium diet predicts cardiac event-free survival. Methods: Adherence to a low-sodium diet was measured using 3 measures in 119 HF patients: (1) self-reported adherence, 1 item from the Self-care of Heart Failure Index scale; (2) a 3-day food diary; (3) 24-hour urinary sodium excretion. Patients were followed up for a median of 297 days to determine cardiac hospitalization or emergency department visit. One-way analysis of variance and Cox regression were used to address our purposes. Results: Self-reported adherence was concordant with adherence to a low-sodium diet measured by food diaries and 24-hour urinary sodium excretion. Thirty-one patients who reported they always follow a low-sodium diet had an average sodium intake less than 3 g/d (F = 5.07, P =.002) and 3.3 g of a mean 24-hour urinary sodium excretion (F = 3.393, P =.020). Patients who reported they never or rarely follow a low-sodium diet had 4.7 times greater risk of having cardiac events than did those who always followed a low-sodium diet (P =.017). Conclusion: Self-reported adherence to a low-sodium diet predicted cardiac event-free survival demonstrating clinicians can use this as an indicator of adherence.