Abstract
OBJECTIVE: Disorders related to serum chloride concentration have recently attracted considerable interest. We sought to determine whether initial serum chloride was associated with an increased risk of all-cause mortality among critically ill patients diagnosed with acute kidney injury (AKI). METHODS: We searched the Multiparameter Intelligent Monitoring in the Intensive Care IV database to retrieve clinical data, including demographic factors, clinical variables, lab tests, and scoring systems. Hypothesis testing was conducted using a range of statistical approaches, including the generalized additive model, the Cox proportional hazards model, and subgroup analyses. RESULTS: Our research included 19,107 participants who met the set criteria. We found that the levels of chloride in the patient's serum upon admission had a similar inverted L-shaped relationship with the 30-day all-cause mortality rate in AKI. In multivariate analysis following the adjustment of confounders such as sex, ethnicity, and age, compared with the referent group (100-105 mmol/L), low-chloride (< 100 mmol/L) was a considerable risk predictor for 30-day, 90-day, and 365-day all-cause mortality. In particular, the HRs (95% CIs) for chloride were 1.49 (1.36, 1.63), 1.48 (1.36, 1.61), and 1.59 (1.47, 1.71). After adjusting additional clinical characteristics, low-chloride levels still served independently as a major predictor of all-cause mortality over 30 days, 90 days, and 365 days (HR, 95% CI: 1.24, 1.09-1.41; 1.17, 1.04-1.32; 1.27, 1.14-1.42). CONCLUSIONS: The probability of all-cause mortality was higher in severely ill individuals with AKI who had lower baseline serum chloride levels upon admission to the intensive care unit (ICU).