The relationship of diuretics and dietary sodium in patients with heart failure: an analysis of the SODIUM-HF trial.

BACKGROUND

SODIUM-HF was a large clinical trial testing dietary sodium restriction compared to usual care in patients with heart failure that showed no reduction in clinical events. It has been suggested that diuretic doses in response to dietary sodium modification may have influenced the trial results.

OBJECTIVE

We assessed the effects of baseline diuretic dose and diuretic dose changes on clinical outcomes in the SODIUM-HF trial.

METHODS

Diuretics were converted to furosemide-equivalent diuretic total daily doses. Furosemide dose was treated as a continuous variable and also stratified into 0mg, 1mg to 39mg, 40mg, 41mg to 80mg, and > 80mg daily. The baseline diuretic dose and change in diuretic dose were assessed and correlated with dietary sodium restriction and changes in dietary sodium intake. We then examined the relationship between diuretic dosing and the primary outcomes of SODIUM-HF (cardiovascular-related emergency department visit, cardiovascular-related hospitalization, and all-cause mortality).

RESULTS

Of the 806 patients enrolled in the SODIUM-HF trial, 784 had known diuretic status at baseline: 209 patients (26.7%) with 0mg, 134 patients (17%) with 1mg to 39mg, 205 patients (26.1%) with 40mg, 118 patients (15.1%) with 41mg to 80mg, and 118 patients (15.1%) with > 80mg. No correlation was found between dietary sodium intake and diuretic dose, either at baseline or change throughout the study (P > .05). For the primary outcomes, the 2-year risk of primary outcomes was strongly correlated with diuretic dose at baseline across the overall SODIUM-HF population (P < .001). No significant association was found between the treatment arm and the risk of primary outcomes, within each baseline diuretic dose range or with change in diuretic dose (both P > .05).

CONCLUSIONS

Although a higher baseline diuretic dose was associated with worse clinical outcomes, no association was found between dietary sodium restriction, baseline or change in diuretic dose and the primary outcomes.