Bronchopulmonary dysplasia (BPD) is a common complication of preterm birth. Very different models using clinical parameters at an early postnatal age to predict BPD have been developed with little extensive quantitative validation. The objective of this study is to review and validate clinical prediction models for BPD. We searched the main electronic databases and abstracts from annual meetings. The STROBE instrument was used to assess the methodological quality. External validation of the retrieved models was performed using an individual patient dataset of 3229 patients at risk for BPD. Receiver operating characteristic curves were used to assess discrimination for each model by calculating the area under the curve (AUC). Calibration was assessed for the best discriminating models by visually comparing predicted and observed BPD probabilities. We identified 26 clinical prediction models for BPD. Although the STROBE instrument judged the quality from moderate to excellent, only four models utilised external validation and none presented calibration of the predictive value. For 19 prediction models with variables matched to our dataset, the AUCs ranged from 0.50 to 0.76 for the outcome BPD. Only two of the five best discriminating models showed good calibration. External validation demonstrates that, except for two promising models, most existing clinical prediction models are poor to moderate predictors for BPD. To improve the predictive accuracy and identify preterm infants for future intervention studies aiming to reduce the risk of BPD, additional variables are required. Subsequently, that model should be externally validated using a proper impact analysis before its clinical implementation.

To evaluate the association between bronchopulmonary dysplasia (BPD) severity and risk of neurodevelopmental impairment (NDI) at 2 years and 5 years corrected age and to examine whether this association changes over time. This single-center retrospective cohort study included patients with a gestational age <30 weeks surviving to 36 weeks postmenstrual age, divided into groups according to BPD severity. NDI was defined as having cognitive or motor abilities below -1 SD, cerebral palsy, or a hearing or a visual impairment. The association was assessed using a multivariate logistic regression model analysis, adjusting for known confounders for NDI, and mixed-model analysis. Of the 790 surviving infants (15% diagnosed with mild BPD, 9% with moderate BPD, and 10% with severe BPD), 88% and 82% were longitudinally assessed at 2 years and 5 years corrected age, respectively. The mixed-model analysis showed a statistically significant increase in NDI at all levels of BPD severity compared with infants with no BPD, and a 5-fold increased risk in NDI was seen from 2 years to 5 years corrected age in all degrees of BPD severity. The strength of this association between NDI and BPD severity did not change over time. Increased BPD severity is associated with increased risk of NDI at both 2 years and 5 years corrected age. The absolute incidence of NDI increased significantly from 2 years to 5 years corrected age for all BPD severity categories, but this increased risk was similar at both time points in each category.

The Platelets for Neonatal Thrombocytopenia (PlaNeT-2) trial reported an unexpected overall benefit of a prophylactic platelet transfusion threshold of 25 × 109/L compared with 50 × 109/L for major bleeding and/or mortality in preterm neonates (7% absolute-risk reduction). However, some neonates in the trial may have experienced little benefit or even harm from the 25 × 109/L threshold. We wanted to assess this heterogeneity of treatment effect in the PlaNet-2 trial, to investigate whether all preterm neonates benefit from the low threshold. We developed a multivariate logistic regression model in the PlaNet-2 data to predict baseline risk of major bleeding and/or mortality for all 653 neonates. We then ranked the neonates based on their predicted baseline risk and categorized them into 4 risk quartiles. Within these quartiles, we assessed absolute-risk difference between the 50 × 109/L- and 25 × 109/L-threshold groups. A total of 146 neonates died or developed major bleeding. The internally validated C-statistic of the model was 0.63 (95% confidence interval, 0.58-0.68). The 25 × 109/L threshold was associated with absolute-risk reduction in all risk groups, varying from 4.9% in the lowest risk group to 12.3% in the highest risk group. These results suggest that a 25 × 109/L prophylactic platelet count threshold can be adopted in all preterm neonates, irrespective of predicted baseline outcome risk. Future studies are needed to improve the predictive accuracy of the baseline risk model. This trial was registered at www.isrctn.com as #ISRCTN87736839.