Relationship between the systemic immune-inflammatory index and the severity of acute bronchiolitis in children

Objective Acute bronchiolitis (AB) is one of the most common respiratory diseases in early childhood and is still an important health problem worldwide. The systemic immune-inflammatory index (SII) is thought to have potential to be a new-generation inflammatory biomarker. We sought to investigate the value of SII for severity assessment in children with AB. Methods A total of 74 AB patients were included in a prospective observational study. Patients were classified into 3 AB groups according to this classification: mild (1-5 points), moderate (6-10 points), and severe (11-12 points). Complete blood count, C-reactive protein, and procalcitonin tests were carried out. Modified Tal score was evaluated to determine severity. The performance of parameters to predict the severity of AB was assessed using the receiver operating characteristic (ROC). Results Whereas neutrophil count (P = .037), neutrophil-to-lymphocyte ratio (P = .030), and SII (P = .030) values increased significantly with disease severity, red cell distribution width (P = .048) values were higher in the moderate AB group. The SII was found to have the highest area under the curve in the comparison of the mild-moderate groups combination and the high group on ROC analysis (P = .009). Conclusion The SII values of pediatric patients hospitalized with the diagnosis of AB were significantly higher in the high-severity group. The SII may offer additional severity stratification in children with AB.