Bronchopulmonary dysplasia to predict neurodevelopmental impairment in infants born extremely preterm.

BACKGROUND

Bronchopulmonary dysplasia (BPD) in extremely low gestational age neonates (ELGANs) was associated with neurodevelopmental impairment (NDI). However, the best endpoint of BPD assessment to predict subsequent NDI remains unclear.

METHODS

We re-analyzed the PREMILOC trial, previously designed to test the effect of prophylactic hydrocortisone on survival without BPD at 36 weeks of postmenstrual age (BPD) in ELGANs, to compare predictive models of NDI considering baseline characteristics, respiratory course up to and BPD status at 36 or 40 weeks of postmenstrual age (BPD/BPD).

RESULTS

Among 404/519 (77.8%) infants enrolled in the trial alive at 2 years of age, all neurocognitive scores were available for 302 (74.8%) patients. Gestational diabetes and sex were identified as the only statistically significant baseline predictors of NDI. Adding BPD to this baseline model was found to be superior to predict NDI compared to BPD, leading to a mean difference of the developmental quotient of -6.7 points (95% confidence interval: -10.0 to -3.50, P < 0.001). The prophylactic hydrocortisone treatment effect on survival without BPD was found to be highly significant (OR = 2.08 [95% confidence interval: 1.36 to 3.17], P < 0.001).

CONCLUSIONS

These data suggest a better accuracy of BPD to predict NDI in ELGANs, an important finding for future clinical trials and research in drug development.

REGISTRATION NUMBERS

EudraCT number 2007-002041-20, ClinicalTrial.gov number, NCT00623740.

IMPACT

The best endpoint to assess BPD as a surrogate to predict neurocognitive impairment in infants born extremely preterm remains unclear. This study strongly suggests a better discriminative value of BPD as assessed at 40 weeks of postmenstrual age (instead of 36 weeks) to predict neurocognitive impairments at 2 years of age in children born extremely preterm. This study supports the switch up to 40 weeks of the primary outcome chosen in future clinical trials designed to prevent BPD. Our data also provide evidence of the beneficial effect of HC on preventing BPD at full-term equivalent age.