Early Predictive Value of the C-reactive Protein-to-Serum Iron Ratio for Severe Mycoplasma pneumoniae Pneumonia in Children

This retrospective single-center study evaluated the predictive value of the C-reactive protein-to-serum iron (CRP/SI) ratio for the early identification of severe Mycoplasma pneumoniae pneumonia (SMPP) in children. A total of 335 children with laboratory-confirmed Mycoplasma pneumoniae pneumonia hospitalized between January and December 2024 were included. Logistic regression analyses were performed to identify independent risk factors for SMPP, and receiver operating characteristic analysis was used to assess diagnostic performance. C-reactive protein, SI, and the CRP/SI ratio were independently associated with SMPP. The CRP/SI ratio demonstrated the best diagnostic performance (area under the curve = 0.90), with an optimal cutoff value of 5.08 yielding a sensitivity of 83.3% and specificity of 82.6%. The CRP/SI ratio may serve as a simple and readily available biomarker for early identification of SMPP in children.