Respiratory outcome of preterms with and without new BPD – differences and analogies with term born infants?

Background: During the past years, new treatment strategies improved survival of preterm infants and led to a change of the picture of BPD. Few data on respiratory outcome of this new BPD in comparison to a reference group are available. Objective: To describe the occurrence of cough and wheeze during the first year after discharge in preterm infants and to compare it to healthy term-born infants. To assess risk factors for severe and common respiratory morbidity during infancy in preterm infants with and without new BPD. Methods: We recruited 128 preterm infants (73 with BPD, mean gestational age 28.0 weeks and 48 without BPD, mean gestational age 31.9 weeks) during initial hospital stay and assessed respiratory morbidity during the first year after discharge by questionnaires to the parents. The term-born cohort was recruited in the same area and time interval. Risk factors for respiratory morbidity were calculated using regression models. Results: The occurrence of cough in the first year after discharge is comparable between the 128 preterm and the 195 term-born infants (80% and 93%, respectively), whereas wheezing occurs more often in preterm infants (44%) than in term-born infants (21%). No difference was found between preterm infants with and without BPD. Risk factors significantly associated with severe respiratory morbidity (such as re-hospitalisation) in preterm infants were history of chorioamnionitis, lower Apgar score at birth and higher peak inspiratory pressure during mechanical ventilation, but interestingly not gestational age. Risk factors significantly associated with common respiratory morbidity (cough or wheeze) in preterm infants were male gender, contact to other children after discharge and maternal smoking during pregnancy, independent of premorbidity. Conclusions: Contrary to risk factors for severe respiratory morbidity, risk factors for cough and wheeze are comparable between preterm and term-born infants. The similar prevalence of wheezing in preterms with and without BPD supports the hypothesis that prematurity is the dominant contributor to impaired airway development.