Low Urinary Sodium Excretion Linked to Higher Mortality
Increased sodium excretion tied to raised systolic blood pressure, but not heart disease risk
WEDNESDAY, May 4 (HealthDay News) -- Lower sodium excretion is associated with an increased risk of cardiovascular disease (CVD) mortality, according to a study published in the May 4 issue of the Journal of the American Medical Association.
Katarzyna Stolarz-Skrzypek, M.D., Ph.D., from the University of Leuven in Belgium, and colleagues investigated whether 24-hour urinary sodium excretion is predictive of blood pressure and health outcomes. Data were collected from 3,681 participants who were split into two cohorts: a hypertension cohort including 2,096 individuals who participated in a hypertension incidence analysis, and a blood pressure cohort comprising 1,499 individuals who were included in analysis of the correlation between blood pressure and 24-hour urinary sodium.
The investigators found that, for all participants there was a significant decrease in CVD deaths during the 7.9-year follow-up across increasing tertiles of 24-hour urinary sodium excretion, with 50 deaths in the low excretion group (mean, 107 mmol), 24 in the medium excretion group (mean, 168 mmol), and 10 in the high excretion group (mean, 260 mmol). This association remained significant after adjusting for confounders. Baseline sodium excretion was not associated with total mortality or fatal and nonfatal CVD events. In the hypertension cohort, there was no increased hypertension risk during a 6.5-year follow-up. In the blood pressure cohort, systolic blood pressure increased significantly after a 6.1-year follow-up, but sodium excretion remained unchanged. After adjusting for confounders, a 100-mmol increase in sodium excretion was correlated with an increase in systolic, but not diastolic blood pressure.
"Lower sodium excretion was associated with higher CVD mortality," the authors write. "Our current findings refute the estimates of computer models of lives saved and health care costs reduced with lower salt intake."