Ionized calcium level predicts in-hospital mortality of severe sepsis patients: A retrospective cross-sectional study

Objective: To evaluate the effect of serum ionized calcium levels on the prognosis of severe sepsis patients. Methods: This retrospective cross-sectional study included sepsis patients who were hospitalized in an intensive care unit between January 2011 and December 2014. The demographic and baseline data of the patients who died and survived were compared. The cutoff value of ionized calcium for in-hospital mortality was determined by the receiver operating characteristics curve (ROC). In-hospital mortalities and the survival rates were compared between patients with different ionized calcium levels. Besides, the risk factor of in-hospital mortality was determined. Results: This study included 145 patients with 113 patients who died in the hospital. The patients who died had significantly lower ionized calcium levels (U=2.25, P=0.034). A cut-off value of 0.93 mmol/L of ionized calcium was determined by the ROC curve. The patients with ionized calcium>0.93 mmol/L showed a significantly lower morality (χ2=9.90, P=0.002) and higher survival rate than with ≤0.93 mmol/L (log rank=6.20, P=0.010). Multivariate Cox regression revealed that ionized calcium ≤0.93 mmol/L was a risk factor of in-hospital mortality. Conclusions: Ionized calcium level≤0.93 mmol/L was an independent predictor of in-hospital mortality of severe sepsis.