Abstract 2236: Three Gram Sodium Intake is Associated with Better Event-Free Survival Only in Patients with Advanced Heart Failure
Background: There is no consensus among published guidelines regarding the recommended level of sodium intake for patients with heart failure (HF), primarily related to a lack of research demonstrating differences in outcomes between patients who do and do not follow a sodium-restricted diet.
Purpose: To compare differences in event-free survival (hospitalization or death) between patients who have 24-hour urine sodium (UNa) excretions above and below levels recommended in two current HF guidelines.
Method: A total of 126 patients (70% male, 61 ± 11 years, 60% NYHA class III/IV, ejection fraction (35 ± 14%) were recruited from an outpatient HF clinic in which a low sodium diet was prescribed. Clinical characteristics and event-free survival (median 348 days) were determined by patient interview and detailed medical record review. 24-hour urines for UNa were collected by patients at home after detailed instructions and used as indicators of dietary sodium intake. A series of survival curves were computed using the Kaplan-Meier method with groups (high vs. low UNa) compared using log rank test:
Patients divided at 131 mmol (3 g) UNa, the recommended upper limit of sodium intake in the HFSA guidelines;
Patients divided at a 174 mmol (4 g) UNa, the recommend upper limit of sodium intake in the ACC/AHA guidelines; and
Same comparisons with groups further stratified by NYHA functional class I/II vs. III/IV.
Results: Mean UNa was 190 ± 96 mmol. There were no differences in event-free survival between patients divided at either 131 mmol (p = .17) or 174 mmol (p = .35) UNa cut points. When stratified by NYHA class, event-free survival in NYHA I/II was similar regardless of UNa cut point (p = .37 and .86, respectively). In contrast, patients in NYHA III/IV with UNa less than 131 mmol had significantly longer event-free survival than those with UNa above 131 mmol (p= .02). Event-free survival,however, was equally poor when NYHA III/IV patients were compared using the 174 mmol UNa cut point (p = .46).
Conclusion: The level of sodium intake of patients at NYHA Class I and II did not affect event-free survival. Patients in Class III and IV had better outcomes if sodium intake was limited to 3 g or less. These data to provide support for 3 g dietary sodium restriction in patients with advanced HF.