Effect of Systemic Immune-Inflammation Index and Inflammatory Markers on Length of Hospital Stay in Diabetic Ketoacidosis: a Retrospective Study

Objective: This study aims to evaluate the effect of the systemic immune-inflammation index (SII) on the length of hospital stay (LOS) in patients with diabetic ketoacidosis (DKA). Materials and methods: Between December 2023 and May 2025, 61 patients aged 18 and over who were admitted with a diagnosis of DKA and without signs of infection were retrospectively examined. The relationship between SII, neutrophil–lymphocyte ratio (NLR), platelet–lymphocyte ratio (PLR), and C-reactive protein to albumin ratio (CAR) values and LOS was evaluated using correlation analysis, multiple linear regression, and receiver operating characteristic (ROC) curve analyses. Results : The study cohort was established by consecutively screening 98 patients who presented to the emergency department with a diagnosis of DKA between December 2023 and June 2025. Thirty-seven patients who did not meet the inclusion criteria were excluded, resulting in a final analytic sample of 61 patients. The mean age of the cohort was 36 years, and 57.4% of the participants were male (n = 35). A significant positive correlation was found between SII, NLR, PLR values and LOS (r = 0.600, r = 0.539, r = 0.403, respectively) (p = 0.00, p = 0.00, p = 0.001, respectively). In the regression analysis, SII emerged as the sole independent predictor of LOS (p = 0.003). In ROC analysis, SII showed the best performance in predicting hospitalization longer than 3 days [area under the curve (AUC): 0.884; 95% CI: 0.794–0.973]. Conclusions: The SII may serve as a biomarker for DKA-associated length of hospitalization. Further research is needed to confirm these findings.