The Role of the Systemic Immune Inflammation Index (SII) as an Indicator of the Hospital Admission Rate among Pediatric Patients with Acute Exacerbation of Asthma: A Retrospective Cohort Study

Background: Asthma is the most common chronic condition among children; it typically involves emergency room visits and stays in hospitals during severe recurrence. Derived from neutrophil, lymphocyte, and platelet counts, the systemic immune inflammation index (SII) may also indicate systemic inflammation and predict clinical outcomes. Objective: This study sought to investigate the correlation between the SII and hospital admissions in children experiencing acute asthma exacerbations and to assess the predictive value of the SII with respect to other hematological indicators over the course of the study. Methods: A total of 172 children (≤14 years) presenting with asthma exacerbations from 2018--2024 were included in a retrospective cohort study at Saudi German Hospital, Medina. Within twenty-four hours of emergency presentation, the SII was computed via CBC data. Assessments of relationships with hospital admission used logistic and Poisson regression methods. Results: With respect to the SII values (2,162 vs. 1,095), admitted patients had noticeably higher values (p < 0.001). For predicting admission, ROC analysis revealed an SII cut-off of 735 (sensitivity 72%, specificity 62%). Independent of age, sex, and BMI, a high SII was associated with doubled admission rates (IRR = 2.22, p = 0.001) and a greater likelihood of hospitalisation (OR = 4.78, 95% CI: 2.47–9.57, p <0.001). Conclusion: In paediatric asthma exacerbations, an elevated SII is an independent predictor of hospital admission; hence, it is valuable for early risk assessment and therapy choices.