ADMISSION RDW-TO-PCV RATIO AS A PREDICTOR OF SEVERE DENGUE IN CHILDREN: A RETROSPECTIVE OBSERVATIONAL STUDY

Abstract

Background: Severe dengue in children can lead to significant morbidity and mortality. Early identification is crucial, yet current predictors are limited in practicality for resource-constrained settings. The red cell distribution width to packed cell volume (RDW/PCV) ratio integrates two pathophysiological processes—anisocytosis and haemoconcentration—and can be derived from a single admission complete blood count (CBC).

Methods: This retrospective observational study included children aged 2–12 years admitted with laboratory-confirmed dengue to a tertiary care centre between November 2022 and June 2025. Demographic, clinical, and laboratory parameters from the first 24 hours were extracted. Severity was classified according to WHO 2009 criteria. Associations were assessed using Kruskal–Wallis tests, ROC analysis, and multinomial logistic regression, with subgroup analyses by age, sex, and diagnosis type.

Results: Among 228 children, 26.8% had mild dengue, 67.5% moderate, and 5.7% severe. Median RDW/PCV increased with severity (mild: 0.327; moderate: 0.328; severe: 0.386; p < 0.001). The ratio predicted severe dengue with an AUC of 0.939 (95% CI 0.880–0.998); the optimal cut-off of 0.3584 achieved 92.3% sensitivity, 87.4% specificity, and 99.5% negative predictive value. Performance remained robust across subgroups (AUC ≥ 0.89). RDW/PCV was independently associated with severity after adjustment for age, sex, platelet count, and diagnosis category (adjusted OR ≈ 77.8 per 0.01 unit; p < 0.001). Higher ratios were also significantly linked to ICU admission (p < 0.001). No significant association was found with length of stay.

Conclusions: The RDW/PCV ratio at admission is a simple, inexpensive marker with high diagnostic accuracy for severe pediatric dengue and excellent utility as a rule-out tool. Its incorporation into triage protocols could enhance early risk stratification and optimize pediatric dengue management.