Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom.
Hypertension. 2013 Nov;62(5):836-43. doi: 10.1161/HYPERTENSIONAHA.113.01793. Epub 2013 Aug 26.
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 19,7101 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.
氯（Cl-）是体内主要的细胞外阴离子，与钠（Na+）相伴，并主要来源于饮食。数据表明，增加膳食中 Cl-的摄入量会升高血压，但矛盾的是，较高的血清 Cl-水平似乎与更低的死亡率和心血管风险相关。这意味着血清 Cl-也反映了独立于血压、血清 Na+和碳酸氢盐（HCO3-）的风险途径。我们分析了 12968 例高血压患者，随访 35 年，使用 Cox 比例风险模型来检验基线血清 Cl-是否是死亡率的独立预测因子。为了区分 Cl-的作用与 Na+和 HCO3-，我们调整了这些电解质，并按 Na+/HCO3-和 Cl-水平进行了分层分析。使用广义估计方程来确定基线 Cl-对随访血压的影响。总风险时间为 197101 人年。血清 Cl-最低五分位数（<100 mEq/L）的全因、心血管和非心血管死亡率比其余患者高 20%。血清 Cl-增加 1 mEq/L 与全因死亡率降低 1.5%（风险比，0.985；95%置信区间，0.98-0.99）相关，校正基线混杂变量以及 Na+、K+和 HCO3-水平后。Na+>135 和 Cl->100 的组具有最佳的生存，与该组相比，Na+>135 和 Cl-<100 的组死亡率显著更高（风险比，1.21；95%置信区间，1.11-1.31）。低而不是高血清 Cl-（<100 mEq/L）与独立于明显混杂因素的更高死亡率风险相关。需要进一步的研究来阐明 Cl-与风险之间的关系。
