Objective: The impact of electrolyte imbalance on clinical outcomes after acute ischemic stroke (AIS) is still not understood. We investigated the association between hypochloremia and hyponatremia upon hospital admission and in-hospital mortality in AIS patients.

Methods: A total of 3314 AIS patients enrolled from December 2013 to May 2014 across 22 hospitals in Suzhou city were included in this study. Hypochloremia was defined as having a serum chloride concentration <98 mmol/L and hyponatremia as having a serum sodium concentration <135 mmol/L. The Cox proportional hazard model was used to examine the effect of hypochloremia and hyponatremia on all-cause in-hospital mortality in AIS patients.

Results: During hospitalization, 118 patients (3.6%) died from all causes. Multivariable model adjusted for age, sex, baseline National Institutes of Health Stroke Scale score, serum sodium, and other potential covariates showed that hypochloremia was associated with a 2.43-fold increase in the risk of in-hospital mortality (hazard ratio [HR] 2.43; 95% confidence interval [CI], 1.41-4.19; P=.001). However, no significant association between hyponatremia (P=.905) and in-hospital mortality was observed. Moreover, the multivariable analysis found that serum chloride (HR=0.92, 95% CI 0.88-0.98; P=.004) but not serum sodium (P=.102) was significantly associated with in-hospital mortality.

Conclusions: Hypochloremia at admission was independently associated with in-hospital mortality in AIS patients.