Association between serum chloride levels and 28-day mortality in geriatric septic ICU patients: A retrospective cohort study

Abstract

Aim: This study aimed to examine whether serum chloride concentrations obtained within the first 24 hours after intensive care unit (ICU) admission are associated with 28-day all-cause mortality in elderly patients with sepsis, which was defined according to Sepsis-3 criteria (suspected infection plus ≥2-point increase in SOFA score) and to explore their potential prognostic value.

Materials and Methods: This retrospective cohort study was conducted at a single center and involved 221 patients aged 65 years and older who were hospitalized in the ICU with sepsis between December 1, 2023 and May 31, 2024. Patient categorisation was based on serum chloride levels measured within the first 24 hours. Patients were categorised as hypochloremic (<95 mEq/L), normochloremic (95–110 mEq/L), or hyperchloremic (>110 mEq/L). Information on demographics, laboratory results, and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores was collected. Data analysis involved the Mann-Whitney U test, the Chi-square test, and logistic regression.

Results: A total of 221 patients were evaluated, with a mean age of 80.87 ± 8.04 years. The 28-day all-cause mortality rate was found to be 67.4%.The prevalence of hyperchloremia (62.4%) was significantly higher than that of normochloremia (25.8%) and hypochloremia (11.8%). Multivariate logistic regression analysis showed that hyperchloremia was an independent predictor of 28-day mortality (OR = 4.95; 95% CI, 1.51–16.21; p = 0.008). A rise in the APACHE II score was found to be a highly significant predictor of mortality (p<0.001).

Conclusion: An independent association between elevated chloride levels and 28-day mortality was observed in elderly septic patients requiring intensive care. Routine monitoring of serum chloride levels and careful management of chloride load may contribute to an improved prognosis in this vulnerable patient population.