The association between BMI trajectories and bronchopulmonary dysplasia among very preterm infants

Objective To investigate the association between change in body mass index (BMI) from birth to 36 weeks gestation (Delta BMI) and bronchopulmonary dysplasia (BPD) among infants born Methods This was a multicenter retrospective cohort study (2015-2018) of infants born z score from birth to 36 weeks corrected age grouped into quartiles of change. Association between Delta BMI z scores and BPD was assessed using generalized linear mixed models. Results Among 772 included infants, 51% developed BPD. From birth to 36 weeks CGA, the weight z score of infants with BPD decreased less than for BPD-free infants, despite a greater decrease in length z score and similar caloric intake resulting in increases in BMI z score (median [IQR], 0.16 [-0.64; 1.03] vs -0.29 [-1.03; 0.49]; P < 0.01). In the adjusted analysis, higher Delta BMI z score quartiles were associated with higher odds of BPD (Q3 vs Q2, AOR [95% CI], 2.02 [1.23; 3.31] and Q4 vs Q2, AOR [95% CI], 2.00 [1.20; 3.34]). Conclusion Among preterm infants, an increase in BMI z score from birth to 36 weeks corrected is associated with higher odds of BPD. Impact Preterm infants with evolving lung disease often experience disproportionate growth in the neonatal period. In this multicenter cohort study, increases in BMI score from birth to 36 weeks CGA were associated with higher odds of BPD. Despite similar caloric intake, infants with BPD had a higher weight- but lower length-for-age, resulting in higher BMI score compared to BPD-free infants. This suggests that infants with evolving BPD may require different growth and nutritional targets compared to BPD-free infants.