Early serum electrolyte profiles in pediatric sepsis and their association with mortality

Electrolyte disturbances are common in pediatric sepsis. This study aimed to identify early electrolyte patterns and evaluate their association with hospital mortality. A retrospective cohort of 1,589 pediatric sepsis patients (30 days-18 years) from the Shanghai Children's Hospital PICU sepsis database (2014 to present) was analyzed. Based on the first electrolyte panel (sodium, potassium, chloride, magnesium, calcium, and phosphate) measured within 24 h of PICU admission, patients were classified into three clusters using k-means clustering. Five Cox proportional hazards regression models were used to assess the association between the three cluster subtypes and hospital mortality. Three distinct clusters were identified: Cluster 1 (high sodium, and chloride; n = 436), Cluster 2 (balanced electrolytes; n = 713), and Cluster 3 (low sodium, chloride, and calcium; n = 440). Overall mortality was 9.63%. Cluster 3 showed higher mortality than Cluster 2 (11.59% vs. 7.43%, Bonferroni-adjusted P = 0.052). In multivariable Cox regression, Cluster 3 was associated with increased mortality risk (Model 3: HR 1.60, 95% CI 1.08-2.38), after adjusting for age, biomarkers, shock, and immunosuppression.

Early electrolyte profiling identifies a high-risk subtype (Cluster 3) characterized by lower levels of sodium, chloride, and calcium, which is associated with higher mortality in pediatric sepsis. The result suggests further investigation could focus on whether targeted early correction of these electrolyte disturbances can improve sepsis outcomes.

• Electrolyte imbalances are highly prevalent in critically ill patients and have been increasingly recognized as prognostic markers in sepsis. Multiple studies have established single electrolyte levels as independent predictors of sepsis mortality, such as hyponatremia, hypokalemia, and hyperphosphatemia.

• The current results support early electrolyte profiling as a readily accessible, low-cost strategy for risk stratification in pediatric sepsis. Cluster 3 (lower levels of sodium, chloride, and calcium) appears to identify a high-risk subgroup with mortality rates exceeding 11%, even after accounting for major confounders.