Association of serum chloride levels with all-cause mortality among patients in surgical intensive care units: a retrospective analysis of the MIMIC-IV database

Abstract This study explores the association between serum chloride concentrations and all-cause mortality among patients in the Surgical Intensive Care Unit (SICU). Employing a retrospective cohort design, the study utilized data extracted from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database, specifically focusing on individuals admitted to the surgical/trauma ICUs. This dataset encompassed demographic profiles, laboratory findings, historical medical data, vital statistics, and variables pertinent to prognosis. Participants were divided into four groups based on their serum chloride concentrations. The primary outcomes assessed were mortality rates at 30, 90, and 180 days post-admission to the ICU. Analytical methods included Kaplan–Meier survival curves, Cox proportional hazards regression models, and Restricted Cubic Spline (RCS) analyses to delineate the relationship between serum chloride concentrations and patient outcomes. The study cohort comprised 10,996 patients, with observed mortality rates of 12.78% at 30 days, 17.14% at 90 days, and 20.32% at 180 days. Kaplan–Meier analyses revealed significant disparities in survival rates across the quartiles of serum chloride during the follow-up intervals (p