Urinary Sodium Concentration Is an Independent Predictor of All-Cause and Cardiovascular Mortality in a Type 2 Diabetes Cohort Population.

Objective: Sodium intake is associated with cardiovascular outcomes. However, no study has specifically reported an association between cardiovascular mortality and urinary sodium concentration (U). We examined the association of U with mortality in a cohort of type 2 diabetes (T2D) patients.

Methods: Patients were followed for all-cause death and cardiovascular death. Baseline U was measured from second morning spot urinary sample. We used Cox proportional hazard models to identify independent predictors of mortality. Improvement in prediction of mortality by the addition of U to a model including known risk factors was assessed by the relative integrated discrimination improvement (rIDI) index.

Results: Participants ( = 1,439) were followed for a median of 5.7 years, during which 254 cardiovascular deaths and 429 all-cause deaths were recorded. U independently predicted all-cause and cardiovascular mortality. An increase of one standard deviation of U was associated with a decrease of 21% of all-cause mortality and 22% of cardiovascular mortality. U improved all-cause and cardiovascular mortality prediction beyond identified risk factors (rIDI = 2.8%, = 0.04 and rIDI = 4.6%, = 0.02, resp.).

Conclusions: In T2D, U was an independent predictor of mortality (low concentration is associated with increased risk) and improved modestly its prediction in addition to traditional risk factors.