Hypochloremia is associated with increased risk of all-cause mortality in patients in the coronary care unit: A cohort study

Objective Serum chloride disorders have been gaining increased attention. We aimed to assess the impact of serum chloride on all-cause mortality in critically ill patients in coronary care units (CCUs). Methods We extracted clinical data from the Multiparameter Intelligent Monitoring in Intensive Care III database. We used data for the first CCU admission of each patient; baseline data were extracted within 24 hours after CCU admission. Statistical methods included the Lowess smoothing technique, Cox proportional hazards model, and subgroup analyses. Results A total 5616 patients who met the inclusion criteria were included. We observed a U-shaped relationship between admission chloride levels and 30-day all-cause mortality. In multivariate analysis adjusted for age, ethnicity, and sex, both hyper- and hypochloremia were significant predictors of risk of 30-day, 90-day, and 365-day all-cause mortality. After adjusting additional clinical characteristics, hypochloremia remained a significant predictor of risk of 30-day all-cause mortality (hazard ratio, 1.47; 95% confidence interval, 1.19-1.83). For 90-day and 365-day all-cause mortality, similar significant robust associations were found. Conclusions We observed a U-shaped relationship between admission chloride levels and 30-day all-cause mortality among patients in the CCU. Hypochloremia was associated with increased risk of all-cause mortality in these patients.