Serum Selenium and Iron as Predictors of Disease Severity and Nutritional Status in Children with Community-Acquired Pneumonia

Background: Pediatric community-acquired pneumonia remains a major cause of morbidity and mortality. Selenium (Se) and iron (Fe) influence host redox balance and “nutritional immunity,” but their relationship to clinical severity in children is not well established. Methods: A cross-sectional study was done on 60 children with CAP admitted to the Pediatric Chest Unit, Zagazig University. Respiratory distress was graded I–IV. Results: Respiratory distress grades were : I (33.3) %, II (33.3) %, III (15.0) %, IV (18.3) %. Oxygen support included: nasal prongs 75.0%, mask 6.7% and mechanical ventilation 18.3%. PICU admission were required in 33.3%. Median (IQR) Fe levels decreased across distress grades (grade I: 76.5; grade II: 70; grades III-IV: 52 µg/dL; Kruskal–Wallis=9.796, p=0.007; pairwise p=0.044 and 0.002). Se likewise declined (grade I: 72.44; grade II: 66.78; grades III-IV: 29.24 µg/dL .Cutoffs predicting grades III – IV distress: Fe ≤ 67 µg/dL (AUC 0.734; sensitivity 90%; specificity 55%; PPV 50%; NPV 91.7%; accuracy 66.7%; p=0.003) and Se ≤ 69.62 µg/dL (AUC 0.763; sensitivity 80%; specificity 52.5%; PPV 45.7%; NPV 84%; accuracy 61.7%; p=0.001). same cutoffs predicted PICU admission with identical performance metrics. Conclusion: Both serum selenium and iron showed a progressive decline increasing severity, and cutoffs of ≤69.62 µg/dL for selenium and ≤67 µg/dL for iron demonstrated moderate accuracy in predicting severe illness supporting the role of selenium and iron as potential biochemical markers of severity in pediatric