Prediction models for refractory Mycoplasma pneumoniae pneumonia and corticosteroid treatment escalation in hospitalized children: a retrospective cohort study.

Abstract

Background Mycoplasma pneumoniae carries a clinically important risk of a refractory course or the need for intensified corticosteroid therapy. No admission-day prediction tool has been validated to identify children at risk for either outcome. Methods Children admitted to a single tertiary centre with a diagnosis of MPP between January 2022 and June 2025 were enrolled in a retrospective cohort study. Two penalised logistic regression models were constructed from routine admission-day clinical and laboratory variables: one targeting RMPP occurrence across the full eligible cohort (Cohort A) and one targeting corticosteroid escalation within the treated subgroup (Cohort B). Candidate predictors were screened by LASSO-penalised regression, and model performance was optimism-corrected via bootstrap resampling. Discrimination, calibration, and clinical utility were assessed by corrected AUC, calibration metrics, and decision curve analysis, with nomograms derived from the final coefficients. Results Of 383 Cohort A patients, 106 met criteria for RMPP. Within Cohort B (n = 197), 61 children (31.0%) required treatment escalation. The RMPP model retained nine admission-day variables, including pre-admission fever duration, log-transformed CRP, LDH, D-dimer, ferritin, the neutrophil-to-lymphocyte ratio, albumin, male sex, and pleural effusion, and yielded an optimism-corrected AUC of 0.847 (95% CI: 0.810-0.886). The escalation model retained four variables (LDH, NLR, ferritin, and CRP), with a corrected AUC of 0.799 (95% CI: 0.747-0.861). Both models achieved good calibration and positive net clinical benefit across decision thresholds from 5% to 60%. Conclusions Our study offers a quantitative framework for stratifying children with MPP by their risk of refractory disease and treatment intensification.