Clinical Predictors of Severe Bronchiolitis and Adverse Hospital Outcomes in Children Under Two Years: A Retrospective Study

Background: Early and accurate risk stratification is crucial in management of severe bronchiolitis among children under two years. This study was undertaken with objectives to identify independent clinical predictors of severe bronchiolitis and validate the established Woods-Downes clinical severity score, and evaluate a novel composite Respiratory Distress Index (RDI) for bedside risk stratification. Material and Methods: In a retrospective observational study by evaluating 100 hospitalized children aged 1 to 24 months admitted with acute bronchiolitis, admission clinical parameters, including demographics, vital signs, and physical examination findings, were noted. The primary outcomes were severe bronchiolitis, prolonged hospitalization (> 5 days), and the requirement for supplemental oxygen. Independent predictors were identified using multivariable logistic regression. The discriminatory abilities of the Woods-Downes clinical severity score and the proposed 6-point RDI were assessed using Receiver Operating Characteristic (ROC) Area Under the Curve (AUC) analysis. Results: The mean age of the cohort was 10.17 ± 6.19 months (62% male). During hospitalization, 44% developed severe bronchiolitis, 67% required a prolonged hospital stay, and 57% needed supplemental oxygen. Multivariable analysis identified tachypnoea (aOR 7.72) at admission and male sex (aOR 2.88) as the strongest independent predictors of severe bronchiolitis. The Woods Downes score demonstrated significant discriminatory ability for predicting severe bronchiolitis (AUC = 0.961) and prolonged hospitalization (AUC = 0.875). The proposed RDI also showed robust diagnostic performance, particularly in predicting the need for supplemental oxygen (AUC = 0.863) and severe disease (AUC = 0.804). Conclusion: The Woods-Downes score and the newly proposed RDI are highly accurate, non-invasive clinical tools for risk-stratifying infants with bronchiolitis at the time of admission. Tachypnoea and male sex can identify high-risk infants for severe bronchiolitis, requiring supplemental oxygen and prolonged hospitalization (>5 days).

Keywords: Bronchiolitis, Respiratory Distress Index, Woods-Downes Score, Risk Stratification, Length of Hospitalization.