Supplementary Material for: Risk factors for neurodevelopmental impairment at two- and five years corrected age in preterm infants with established bronchopulmonary dysplasia

Introduction: The objective of this study was to identify risk factors for neurodevelopmental impairment (NDI) at two- and five-years corrected age (CA) in a cohort of preterm infants with established bronchopulmonary dysplasia (BPD).

Methods: This single center retrospective cohort study included infants born between 2009 and 2016 at a gestational age < 30 weeks with moderate or severe BPD at 36 weeks’ postmenstrual age. Perinatal characteristics, (social) demographics, and comorbidities were collected from the electronic patient records. Odds ratios for NDI were calculated with univariate and multivariate logistic regression analyses adjusting for potential confounders.

Results: Of the 602 eligible infants, 123 infants were diagnosed with BPD. NDI was present in 30.3%, and 56.1% at two- and five-years CA, respectively. The only independent risk factors associated with NDI in the multivariate analyses were birthweight (adjusted odds ratio (aOR) 0.74, 95%CI 0.57-0.95; aOR 0.70, 95%CI 0.54-0.91, respectively), small for gestational age (SGA) (aOR 3.25, 95%CI 1.09-9.61; aOR 5.44, 95%CI 1.62-18.2, respectively) at both time points, and male gender at five-years CA (OR 2.49, 95%CI 1.11-5.57).

Discussion/Conclusion: Birthweight and SGA are independent risk factors for NDI at two- and five-years CA and male gender at five-years CA in preterm infants with BPD. In contrast, well known other risk factors for NDI in the general population of preterm infants, such as GA, maternal education, and neonatal comorbidities were not independently associated with NDI.