Investigations Related to Dietary Sodium in Chronic Heart Failure

Sodium restriction is the primary dietary therapy for individuals with heart failure (HF); however, there is little information available to support or refute the use of sodium restriction to manage HF. The overall goal of this work was to generate data related to dietary sodium in patients with chronic HF that would contribute to the development of evidence-based guidelines. The specific objectives were to investigate the optimal methods for measuring sodium intake in HF, to describe the habitual consumption of sodium and other nutrients in HF, and to evaluate the relationship between sodium intake and clinical outcomes in HF. We studied stable ambulatory HF patients who were optimally medicated and participating in multidisciplinary HF programs. We determined that: (1) a strong relationship exists between 24-hour urine collections and food records for sodium intake assessment in non-HF cardiac patients and HF patients not taking loop diuretics. However, the relationship between urinary sodium excretion and sodium intake in HF patients taking loop diuretics was disturbed, suggesting that food records may be a better method for estimating sodium intake in this group. (2) Mean sodium intake in HF and non-HF cardiac patients was similar, and approximately half of patients in each group had sodium intake levels that exceeded the Dietary Reference Intakes tolerable upper level of 2300 mg/d. We also found that both groups had inadequate intakes of several nutrients, including potassium, calcium, magnesium, folate, and vitamin D and E. (3) Finally, we showed that a high sodium diet (>2800 mg/day) in HF was associated with risk of acute decompensated HF, all-cause hospitalization, and all-cause mortality over a median 3 year follow-up period. This is the first published study that prospectively related sodium intake to clinical outcomes in HF. In summary, these data provide novel contributions related to the measurement of sodium intake that can be used in clinical or academic settings. We also describe inadequacies in intake of several vitamins and minerals, which could be addressed through dietary counselling. Finally, we importantly offer insight into a threshold of sodium intake (>2800 mg/day) that could contribute to adverse clinical outcomes in HF.Ph