Serum chloride is an independent predictor of mortality in hypertensive patients

McCallum, L. et al. (2013) Serum chloride is an independent predictor of mortality in hypertensive patients. Hypertension, 62(5), pp. 836-843. (doi: 10.1161/HYPERTENSIONAHA.113.01793)

Abstract

Chloride (Cl−) is the major extracellular anion in the body, accompanying sodium (Na+), and is primarily derived from dietary sources. Data suggest that increased dietary Cl− intake increases blood pressure, yet paradoxically, higher serum Cl− appears associated with lower mortality and cardiovascular risk. This implies that serum Cl− also reflects risk pathways independent of blood pressure, serum Na+, and bicarbonate (HCO3−). We analyzed 12 968 hypertensive individuals followed up for 35 years, using Cox proportional hazards model to test whether baseline serum Cl− was an independent predictor of mortality. To distinguish the effect of Cl− from Na+ and HCO3−, we adjusted for these electrolytes and also performed the analysis stratified by Na+/HCO3− and Cl− levels. Generalized estimating equation was used to determine the effect of baseline Cl− on follow-up blood pressure. The total time at risk was 197 101 person-years. The lowest quintile of serum Cl− (<100 mEq/L) was associated with a 20% higher mortality (all-cause, cardiovascular and noncardiovascular) compared with the remainder of the subjects. A 1 mEq/L increase in serum Cl− was associated with a 1.5% (hazard ratio, 0.985; 95% confidence interval, 0.98–0.99) reduction in all-cause mortality, after adjustment for baseline confounding variables and Na+, K+, and HCO3− levels. The group with Na+>135 and Cl−>100 had the best survival, and compared with this group, the Na+>135 and Cl−<100 group had significantly higher mortality (hazard ratio, 1.21; 95% confidence interval, 1.11–1.31). Low, not high Serum Cl− (<100 mEq/L), is associated with greater mortality risk independent of obvious confounders. Further studies are needed to elucidate the relation between Cl− and risk.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hastie, Dr Claire and Patel, Dr Rajan and Morrison, Dr David and Muir, Dr Scott and Walters, Professor Matthew and Freel, Dr Marie and Mccallum, Dr Linsay and Dawson, Professor Jesse and McInnes, Professor Gordon and Padmanabhan, Professor Sandosh and Dominiczak, Professor Anna and Sloan, Mr Billy and Sattar, Professor Naveed
• Authors: McCallum, L., Jeemon, P., Hastie, C.E., Patel, R.K., Williamson, C., Redzuan, A.M., Dawson, J., Sloan, W., Muir, S., Morrison, D., McInnes, G.T., Freel, E.M., Walters, M., Dominiczak, A.F., Sattar, N., and Padmanabhan, S.
• College/School: College of Medical Veterinary and Life Sciences > School of Health & Wellbeing > Public Health; College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health; College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
• Journal Name: Hypertension
• Publisher: American Heart Association
• ISSN: 0194-911X
• ISSN (Online): 1524-4563