A high-sodium diet is associated with acute decompensated heart failure in ambulatory heart failure patients: a prospective follow-up study.

BACKGROUND: A low-sodium diet is an accepted treatment of patients with heart failure (HF), although minimal evidence exists on the appropriate amount of sodium intake for this population. Certain HF guidelines have liberalized dietary sodium recommendations, which actually exceed guidelines for healthy adults.
OBJECTIVES: We tested the hypothesis that high sodium intake is related to acute decompensated HF (ADHF) in ambulatory HF patients. Secondary outcomes included all-cause hospitalization and mortality.
DESIGN: We prospectively enrolled medically stable, ambulatory patients with systolic HF (n = 123; mean ± SD age: 60 ± 13 y) from 2 outpatient HF clinics from 2003 to 2007. Baseline estimates of dietary sodium and other nutrient intakes were obtained from two 3-d food records.
RESULTS: The median follow-up time was 3.0 y. Mean (±SD) sodium intakes were 1.4 ± 0.3, 2.4 ± 0.3, and 3.8 ± 0.8 g Na/d in the lower, middle, and upper tertiles, respectively. Cumulative ADHF event rates at 3 y were 12 ± 6%, 15 ± 7%, and 46 ± 11% in the low, middle, and upper tertiles, respectively (log-rank P = 0.001). For ADHF, the upper tertile was associated with an adjusted hazard ratio of 2.55 (95% CI: 1.61, 4.04; P < 0.001). Time-to-event probabilities were significant for mortality (log-rank P = 0.022) but not for all-cause hospitalization (log-rank P = 0.224). The high-sodium tertile was associated with an adjusted hazard ratio of 1.39 (95% CI: 1.06, 1.83; P = 0.018) for all-cause hospitalization and 3.54 (95% CI: 1.46, 8.62; P = 0.005) for mortality.
CONCLUSIONS: To our knowledge, this study provides the first prospective evidence that ambulatory HF patients who consume higher amounts of sodium are at greater risk of an ADHF event. These data provide support for more stringent sodium intake guidelines than those currently recommended for HF patients.