Pulmonary Function
Spirometry values were significantly lower in the EP-BPD group than in
the other groups (Table 2, Figure 2). There were no statistically
significant differences in spirometry between the EP-noBPD and MLP
groups. The percentage of patients with spirometry parameters below the
lower limit of normal (LLN) (1.645 standard deviations below the
predicted value) was significantly higher in the EP-BPD group than in
the other groups (Table 2). The unadjusted analysis showed that the
percentage of positive results in bronchodilator testing was higher in
the EP-BPD group than in the other groups, but the differences were not
statistically significant.
The adolescents in the EP-BPD group had significantly greater
air-trapping (represented by the ratio RV/TLC) than those in the MLP
group. There were no differences in the remaining plethysmographic
parameters between groups. DLCO values were
significantly lower in the EP groups, regardless of whether participants
had BPD, than in the MLP group. KCO values were also
lower in the EP groups, but the differences only reached significance
between the EP-NoBPD and MLP groups (E-table 2).
In the adjusted regression models, the percentage of positive results in
bronchodilator testing became significantly higher in the EP-BPD group
than in the other groups (E-table 3). In addition, RV/TLC was
significantly higher in the BPD group than in the EP-noBPD group
(E-table 4). Moreover, pulmonary function differences between groups
remained similar to those found in the unadjusted analysis.
The adolescents in the “high severity” BPD subgroup had significantly
worse spirometry results than those in the “low severity” BPD
subgroup,
but
there were no differences in lung volume or diffusion measurements.
These 2 subgroups were comparable in terms of GA and birth weight
(E-table 5).