Prognostic Values of Serum Chloride and Sodium Levels in Patients with Three-vessel Disease

Objective Identification of new risk factors is needed to improve prediction of adverse outcomes in patients with three-vessel disease(TVD). The present study aimed to evaluate the prognostic values of serum chloride and sodium levels in patients with TVD. Methods We used data from a prospective cohort of consecutive patients with angiographically confirmed TVD. The primary endpoint was all-cause death. Cox proportional hazard regression was used to analyze the relationship of serum chloride and sodium levels with long-term outcomes of TVD patients. Results A total of 8,318 participants with available serum chloride and sodium data were included in this analysis. At baseline, patients in the low tertiles group of serum chloride level(≤ 102.0 mmol/L) or serum sodium level(≤ 139.0 mmol/L) had more severe disease conditions. During a median follow-up of 7.5-year, both low serum chloride level and low serum sodium level were found to be associated with an increased risk for mortality in univariate analysis. However, when both parameters were incorporated into a multivariate model, only low serum sodium level remained to be an independent predictor of all-cause death(hazard ratio: 1.16, 95% confidence interval: 1.01-1.34, P = 0.041). Modest but significant improvement of discrimination was observed after incorporating serum sodium level into the Synergy between percutaneous coronary intervention(PCI) with Taxus and Cardiac Surgery score. Conclusion Serum sodium level is more strongly associated with long-term outcomes of TVD patients compared with serum chloride level. Low serum sodium level is an independent risk factor for mortality, but only provides modest prognostic information beyond an established risk model.