Abstract 433: Serum Chloride is an Independent and Robust Predictor of Mortality Than Serum Sodium, Potassium or Bicarbonate in Hypertensive Patients
Objectives: Extremes of serum Na+, K+ and HCO3 have been associated with poorer outcomes. The role of serum Cl- has been largely considered to be linked to serum Na+ and HCO3 levels.
Design and Methods: We studied the association of serum and other serum electrolytes in relation to mortality outcomes in 13,415 hypertensive patients attending the Glasgow Blood Pressure Clinic (GBPC) with serum Cl- assessed at the registration visit. Cox proportional hazards (Cox-PH) models were used for survival analysis. To determine whether Cl- effects are independent of low serum sodium, we performed the analysis in subjects with Na+ >135 and stratified by Na+ and Cl- levels.
Results: The total time at risk was 197,101 person years during which 3,373 all-cause deaths occurred. Compared to quintile 1 (Cl-<=100), each higher quintile of Cl- was associated with lower mortality (H.R.[95%C.I.]0.82[0.74-0.90];0.79[0.71-0.87];0.79[0.70-0.89];0.80[0.68-0.93]) after adjustment for all conventional risk factors, other serum electrolytes and diuretic use (Figure-1). In the subset with Na+>135, each unit increase in Cl- was associated with a 3% reduction in mortality(H.R =0.97 CI:0.96-0.98). Finally subjects with Na+>135&Cl->100(reference) had the best survival and those with Na+<135 and Cl-<100 the poorest survival. The group with normal Na+>135 and Cl-<100 had significantly higher mortality than the reference group (1.21[1.11-1.31]).
Conclusion: Serum Cl- independently predicts mortality outcomes in the hypertensive population irrespective of serum Na+, K+ and HCO3 levels.
- © 2012 by American Heart Association, Inc.