Predictive analysis of lung function in school-age children born with very low birthweight, according to the definition used of bronchopulmonary dysplasia. A retrospective observational analysis

Abstract

Aim: To determine the predictive value of the definition of bronchopulmonary dysplasia (BPD) on spirometric parameters of very low birthweight (VLBW) children of school age between 1 January 2008 and 31 December 2016. Methods: In this longitudinal retrospective observational study, we analyse a cohort of children admitted to a neonatal intensive care unit between 1 January 2008 and 31 December 2016. All newborns weighing <1500 g and born before 32 weeks of gestational age were included in the study (VLBW newborns). The existence of BPD was established retrospectively according to the definitions proposed by the National Institutes of Health (NIH) in 2001 and the National Institute of Child Health and Human Development (NICHD) in 2018. Lung function of the school-age cohort was evaluated prospectively as FEV1, FVC, FEF25–75% and FEV1/FVC by spirometry. The predictive analysis was performed by multivariate linear regression. Results: Of the 145 children included in the study cohort, 60 were diagnosed with BPD according to the NIH definition and 36 according to that of the NICHD. Lung function was reduced by about 20% in patients with BPD, irrespective of the definition applied. However, the predictive regression model only produced a statistically significant fit with the spirometric variables when the NIH definition was adopted. Conclusions: Our findings highlight the value of continuing to consider oxygen requirements at 28 days of chronological age in the definition of BPD, in order to obtain higher quality predictions of lung function parameters assessed later, during school age.