Association between rapid serum sodium correction and rhabdomyolysis in water intoxication: a retrospective cohort study

BACKGROUND Patients with water intoxication may develop rhabdomyolysis. Existing studies suggest a relationship between the serum sodium correction rate and rhabdomyolysis. The aim of the present study was to determine the association between the sodium correction rate and rhabdomyolysis in patients with water intoxication. METHODS Medical records from all cases of water intoxication presenting to the emergency department and admitted to a single tertiary emergency hospital between September 2012 and August 2016 were examined retrospectively. Serum sodium correction rate was defined as the difference in serum sodium levels at admission and approximately 24 h after admission, divided by time. The primary outcome was rhabdomyolysis, defined as peak creatine kinase level ≥ 1500 IU/L. Logistic regression analysis was used to calculate the adjusted odds ratio of the serum sodium correction rate controlling for age, sex, convulsion, lying down for >8 h before admission to the emergency department, and serum sodium level on admission. RESULTS A total of 56 cases of water intoxication were included in the study. The median serum sodium correction rate was 1.02 mEq/L/h, and 32 patients (62.5%) had rhabdomyolysis. Logistic regression analysis showed that serum sodium correction rate was an independent risk factor of rhabdomyolysis (adjusted odds ratio, 1.53 per 0.1 mEq/L/h; 95% confidence interval, 1.18-1.97). CONCLUSIONS Rapid correction of serum sodium was associated with rhabdomyolysis in patients with water intoxication. Therefore, strict control of serum sodium levels might be needed in such patients.