Impact of Dietary Sodium Restriction on Heart Failure Outcomes

OBJECTIVES This study sought to evaluate the impact of sodium restriction on heart failure (HF) outcomes. BACKGROUND Although sodium restriction is advised for patients with HF, data on sodium restriction and HF outcomes are inconsistent. METHODS We analyzed data from the multihospital HF Adherence and Retention Trial, which enrolled 902 New York Heart Association functional class II/III HF patients and followed them up for a median of 36 months. Sodium intake was serially assessed by a food frequency questionnaire. Based on the mean daily sodium intake prior to the first event of death or HF hospitalization, patients were classified into sodium restricted (<2,500 mg/d) and unrestricted (>= 2,500 mg/d) groups. Study groups were propensity score matched according to plausible baseline confounders. The primary outcome was a composite of death or HF hospitalization. The secondary outcomes were cardiac death and HF hospitalization. RESULTS Sodium intake data were available for 833 subjects (145 sodium restricted, 688 sodium unrestricted), of whom 260 were propensity matched into sodium restricted (n = 130) and sodium unrestricted (n = 130) groups. Sodium restriction was associated with significantly higher risk of death or HF hospitalization (42.3% vs. 26.2%; hazard ratio [HR]: 1.85; 95% confidence interval [CI]: 1.21 to 2.84; p = 0.004), derived from an increase in the rate of HF hospitalization (32.3% vs. 20.0%; HR: 1.82; 95% CI: 1.11 to 2.96; p = 0.015) and a nonsignificant increase in the rate of cardiac death (HR: 1.62; 95% CI: 0.70 to 3.73; p = 0.257) and all-cause mortality (p = 0.074). Exploratory subgroup analyses suggested that sodium restriction was associated with increased risk of death or HF hospitalization in patients not receiving angiotensin-converting enzyme inhibitor or angiotensin receptor blocker (HR: 5.78; 95% CI: 1.93 to 17.27; p = 0.002). CONCLUSIONS In symptomatic patients with chronic HF, sodium restriction may have a detrimental impact on outcome. A randomized clinical trial is needed to definitively address the role of sodium restriction in HF management. (A Self-management Intervention for Mild to Moderate Heart Failure [HART]; NCT00018005) (C) 2016 by the American College of Cardiology Foundation.