Independent risk factors and predictive model for high hospitalization costs in children with Mycoplasma pneumoniae pneumonia

Mycoplasma pneumoniae pneumonia (MPP) can impose substantial healthcare burden in children. Because retrospective severity definitions can be heterogeneous, we used total hospitalization cost as a complementary high–resource-use phenotype and aimed to identify admission-time predictors of high cost and develop an early prediction model. We retrospectively enrolled 402 hospitalized children with MPP at Shantou Central Hospital, China (Jan–Dec 2024). A Gaussian mixture model (GMM) was fitted to total hospitalization cost to derive a data-driven threshold for a high-cost (high–resource-use) subgroup. Using variables available within the first 24 h of admission, we developed a logistic model including age, Tmax, lactate dehydrogenase (LDH), and radiographic consolidation, and then evaluated an age × consolidation interaction. Discrimination was assessed by ROC AUC; age-stratified analyses were used to interpret joint age–consolidation patterns. A data-driven cost threshold identified a high-cost subgroup (> 7,139 RMB; 41/402, 10.2%), defined a posteriori from the observed hospitalization-cost distribution. High-cost cases had longer length of stay, more frequent intensive management (bronchoalveolar lavage and systemic corticosteroids), and a higher prevalence of consolidation. The four-variable model showed good discrimination (AUC 0.790), which improved after adding the age × consolidation interaction (AUC 0.838). Inflammatory markers were higher in consolidation-positive patients, with the largest differences observed in younger children; correspondingly, the interaction model identified younger children with consolidation as having the highest predicted high-cost risk. In this single-center retrospective cohort, hospitalization cost operationalized a high–resource-use phenotype in pediatric MPP. An admission-time model incorporating an age × consolidation interaction may support early risk stratification and resource planning in similar settings; external validation is needed before clinical use.