Predictors of Severity of Diabetic Ketoacidosis in Children with Type 1 Diabetes Mellitus: A Combination of the Monocytes-to-Lymphocyte Ratio (MLR), Neutrophil-to-Lymphocyte Ratio (NLR) and Systemic Immune Inflammation Index (SII): A Retrospective Cohort Study

Background Children's most severe acute consequence from type 1 diabetes mellitus (T1DM) is diabetic ketoacidosis (DKA). Improving outcomes requires early recognition of severe DKA. Recent studies point to inflammatory indices such the monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte ratio (NLR), and systemic immune-inflammation index (SII) as prognostic markers for disease severity in many acute and chronic conditions. Nevertheless, the extent of their involvement in paediatric DKA is still being investigated. Method This retrospective cohort research included ninety children with Type 1 Diabetes Mellitus (T1DM) who were admitted to the paediatric intensive care unit (PICU) with diabetic ketoacidosis (DKA). Patients were categorized in accordance with the severity of DKA (mild, moderate, or severe). Laboratory and clinical data were collected, and inflammatory indicators (MLR, NLR, and SII) were computed. ROC curve analysis were used to determine optimum thresholds, and ordinal logistic regression models were developed to identify independent predictors of DKA severity. Results Children with severe DKA (p < 0.001) had notably higher MLR, NLR, and SII. While MLR showed the highest specificity (84%), SII had the best sensitivity (95%) for predicting severe DKA. High MLR (≥ 0.24) was found independently by multivariate analysis to be a predictor of severe DKA (OR = 8.71; 95% CI: 2.55–33.1; p = 0.001). SII indicated a substantial correlation but did not reach statistical relevance (p = 0.075), while NLR was not a significant independent predictor. Conclusion For paediatric T1DM patients, MLR and SII show promising biomarkers for assessing the severity of DKA. Providing possible use for early risk classification and guiding clinical decision-making in acute care environments, these indices are easily obtained from regular blood tests and very affordable.