Strengths and Limitations
This study has several limitations. First, we excluded patients with severe neurological sequelae and other conditions that could cause further deterioration of pulmonary function and quality of life; therefore, our results cannot be extrapolated to all EP adolescents. Second, we did not include a control group of adolescents who were born full-term. Therefore, interpretation of the degree of lung dysfunction and asthma symptoms is partially limited. Because studies on pulmonary function and respiratory morbidity in MLP adolescents are limited and the findings are discordant, we considered the inclusion of an MLP group to be appropriate. Further studies are needed to better understand the repercussions of moderate and late prematurity on long-term pulmonary development. Third, there was a high percentage of participants with sensitization to allergens in the MLP group. Although analyses of pulmonary function and respiratory morbidity were adjusted for this potential confounder, there might be an overestimation of the prevalence of symptoms such as night-time coughing or lifetime wheezing. However, the prevalence of asthma symptoms in this group did not appear to be higher than that in the general population. Fourth, considering the variability of criteria used to define BPD at the time of diagnosis between the centers, the EP-BPD adolescents were a heterogeneous group. We regrouped the EP-BPD adolescents according to BPD severity into 2 subgroups, and the main differences between them have been reported. Although the “high severity” subgroup had higher respiratory morbidity during follow-up and worse spirometry results than the “low severity” subgroup, the prevalence of current asthma symptoms and quality of life scores in the “high severity” subgroup were similar to those in the “low severity” subgroup and remaining groups. Fifth, this was not a prospective study that allowed for real follow-up of patients over time.
The main strength of the study is that it gathered information on lung function, asthma symptom prevalence, and quality of life in a broad sample of participants with different degrees of prematurity. Given that data on pulmonary function and respiratory morbidity in adolescents with “new” BPD are still limited, we believe that the present findings contribute to a better understanding of the underlying mechanisms of this disease. Since “new” BPD is a constantly moving target that changes over time, further periodical studies are needed because the number of EP infants who survive is increasing, and continuous advances in neonatal care will have an impact on long-term outcomes.