Methods
Study Population: Children with the diagnosis of BPD and seen
in the Children’s Hospital of Philadelphia outpatient pulmonary clinics
between 2016-2021 were identified using electronic medical records
(EMR). Inclusion criteria included birth prior to 34 weeks gestational
age, a diagnosis of BPD by the 2001 National Heart, Lung, and Blood
Institute (NHLBI) consensus statement, (13) and being 8 years of age or
less at their first pulmonary clinic visit. Those who had tracheostomies
and/or were ventilator-dependent were excluded. Inhaled corticosteroid
(ICS) use and timing of initiation were determined by chart review.
History of pulmonary hypertension
was determined by chart review. Outcomes included asthma diagnosis and
acute care usage before and after their first pulmonary visit.
This study was approved by the
Children’s Hospital of Philadelphia Institutional Review Board (IRB#
20-017614) under exempt research. ICD-10 codes were used to identify
children with the diagnosis of BPD with or without the diagnosis of
asthma. These ICD codes were: P27.1, P27.1 + J45, P27.9 and P27.9 + J45.
Statistics: Descriptive means and frequencies were compared
using t tests and chi square tests, respectively (Tables 1 and 3
and Supplemental Tables 1-3). Odds ratios for admissions and visits were
derived from logistic regressions adjusted for potential confounders
that were selected a priori , including gestational age, birth
weight, supplemental oxygen use at NICU discharge, and duration of
follow-up time (i.e., either time between NICU discharge and first
pulmonary visit or time between first pulmonary visit and time of chart
review) (Table 4). The odds ratio for a diagnosis of asthma was derived
similarly, except age at last follow-up was substituted for duration of
follow-up time. Kaplan-Meier analyses were used to assess differences
between groups for time until the diagnosis of asthma (Figure 1). Stata
IC 15 (StataCorp, LLC; College Station, TX) was used for all analyses. P
values of less than 0.05 were defined as significant.