Abstract
BACKGROUND: While chloride (Cl) is the most abundant anion in the serum, it is unfortunately one of the most commonly disregarded laboratory test results routinely drawn upon admission into the medical intensive care unit (MICU). We aimed to investigate the relation between in-hospital mortality, different pathologies requiring admission to the MICU, serum Cl levels, and other biochemical tests in a tertiary center. METHODS: The prospective study included data from 373 patients admitted to the ICU of a tertiary care center between 2017 and 2019. Data of patients under 18, pregnant patients or patients who were in the MICU for under 48 h were excluded. Comorbidity status, complete blood count, biochemistry tests, and blood gas analysis results of all patients included in the study were collected and recorded. Univariate and multivariate analyses were performed with the obtained data. RESULTS: : Of the patients included in the study, 158 (42.4%) were discharged, and 215 (57.6%) died. In the receiver operator characteristics curve analysis performed to determine the discriminating power of Cl levels with a cut-off value of >98 mEq/L in relation to mortality, its sensitivity was found to be 84% and specificity 60%. According to Kaplan-Meier analysis results, mortality rate was higher (60% vs 46%) and survival time was lower (19.0 ± 1.46 vs. 23.0 ± 4.36 days; p = 0.035) in the patient group with high Cl levels compared to the patient group with normal or low Cl levels. In the Cox regression analysis, it was found that the survival time of the patients hospitalized in the MICU was associated with the variables of Cl, presence of cancer diagnosis and pCO2 (hazard ratio: 1.030 (1.008-1.049), 2.260(1.451-3.500), and 1.020 (1.003-1.029); p < 0.05, respectively). DISCUSSION: Mortality in MICU patients were found to increase in association with higher Cl levels at admission, presence of cancer disease, and higher pCO2 levels. In addition, it should not be ignored that there may be an important relationship between renal failure and hyperchloremia in MICU patients.