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.