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

摘要

Objective. Sodium intake is associated with cardiovascular outcomes. However, no study has specifically reported an association between cardiovascular mortality and urinary sodium concentration (U_(Na)). We examined the association of U_(Na) with mortality in a cohort of type 2 diabetes (T2D) patients. Methods. Patients were followed for all-cause death and cardiovascular death. Baseline U_(Na) 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_(Na) to a model including known risk factors was assessed by the relative integrated discrimination improvement (rIDI) index. Results. Participants (n = 1,439) were followed for a median of 5.7 years, during which 254 cardiovascular deaths and 429 all-cause deaths were recorded. U_(Na) independently predicted all-cause and cardiovascular mortality. An increase of one standard deviation of U_(Na) was associated with a decrease of 21% of all-cause mortality and 22% of cardiovascular mortality. U_(Na) improved all-cause and cardiovascular mortality prediction beyond identified risk factors (rIDI = 2.8%, P = 0.04 and rIDI = 4.6%, P = 0.02, resp.); Conclusions. In T2D, U_(Na) was an independent predictor of mortality (low concentration is associated with increased risk) and improved modestly its prediction in addition to traditional risk factors.