Development and validation of a nomogram for predicting recurrent plastic bronchitis in children with Mycoplasma...

Plastic bronchitis (PB) is a complication of Mycoplasma pneumoniae pneumonia (MPP) in children, characterized by bronchial cast formation and airway obstruction. Recurrence after bronchoscopic cast removal can occur, and tools for early risk prediction are limiting. This study aimed to develop and externally validate a nomogram for predicting recurrent PB in children with MPP after initial bronchoscopic cast removal.

This retrospective multicenter cohort study included pediatric patients with MPP complicated by PB. Patients from one center were randomly divided into a training cohort and an internal validation cohort at a ratio of 8:2, while an independent cohort from another tertiary hospital served as the external validation chort. Candidate predictors were screened using least absolute shrinkage and selection operator (LASSO) regression, followed by multivariable logistic regression to identify independent predictors and develop the prediction model. Model performance was evaluated by discrimination, calibration, and clinical utility using receiver operating characteristic (ROC) curves, calibration plots, the Hosmer-Lemeshow goodness-of-fit test, and decision curve analysis (DCA).

A total of 352 children with MPP complicated by PB were included, with 281 patients in the training cohort and 71 in the internal validation cohort. An additional 44 patients from an independent center formed the external validation cohort. Four variables were identified as independent predictors of PB recurrence: serum albumin (ALB), fever persisting for ≥72 h after the first bronchoalveolar lavage (BAL), atelectasis, and bronchial casts involving ≥2 lung lobes. These predictors were incorporated into a nomogram. The model showed discrimination across the three cohorts, with an area under curve (AUC) of 0.853 in the training cohort, 0.833 in the internal validation cohort, and 0.811 in the external validation cohort. Calibration plots showed agreement between predicted and observed risks, and decision curve analysis indicated a higher net benefit than the treat-all and treat-none strategies across a range of threshold probabilities.

We developed and externally validated a nomogram to predict PB recurrence in children with MPP using routinely available clinical and bronchoscopic variables. The model showed consistent discrimination and calibration. Its potential clinical utility for risk stratification and post-procedural monitoring requires further prospective evaluation.