Risk factors for pulmonary consolidation in 316 pediatric cases of chlamydia pneumoniae pneumonia: a single-center retrospective study

Chlamydia pneumoniae (CP) infection in children is increasingly recognized, with a growing proportion developing pulmonary consolidation. Early identification of risk factors is critical for timely intervention, yet systematic pediatric studies remain limited. We aimed to identify independent predictors of pulmonary consolidation and develop a nomogram for individualized risk assessment. This retrospective study enrolled 316 children with Chlamydia pneumoniae pneumonia (CPP) at Hebei Children’s Hospital (Jan–Dec 2025), divided into consolidation ( n = 79) and non-consolidation ( n = 237) groups. Demographic, clinical, laboratory, and imaging data were compared between the two groups. Multivariable logistic regression was used to screen for independent predictors, which were then incorporated into a nomogram. Model discrimination was assessed by the area under the receiver operating characteristic curve ( AUC ), and calibration was evaluated using the Hosmer-Lemeshow test and a calibration curve with 1000 bootstrap resamples. Multivariable analysis identified age, pre-admission illness duration, peak temperature, platelet count (PLT), C-reactive protein (CRP), and D-dimer as independent predictors (all P < 0.05). A nomogram was constructed based on peak temperature, PLT, CRP, and D-dimer. The nomogram showed good discriminative ability, with an AUC of 0.868 (95% CI : 0.823–0.912). Calibration was satisfactory: the bias-corrected curve closely followed the 45-degree ideal reference line, with a mean absolute error of 0.022, indicating excellent model calibration, and the Hosmer-Lemeshow test confirmed good fit ( χ² = 9.736, df = 8, P = 0.284). At the optimal cutoff, the model yielded a sensitivity of 79.7% and a specificity of 79.7%. The combined model (peak temperature, PLT, CRP, and D-dimer) demonstrated promising discrimination for identifying pulmonary consolidation in children with Chlamydia pneumoniae pneumonia. The identified cutoffs may indicate increased risk of existing consolidation and could support early risk stratification. However, given the retrospective cross-sectional design, these findings should be interpreted as associations rather than prospective predictions; external validation in prospective studies is required before clinical application.