Comparison of lung function during the study period according to
the prognosis
Twenty-one subjects repeated PFTs regularly for 24 months after BOS
occurred. Among them, nine children did not complete PFTs because they
are died or underwent lung TPL within 24 months after BOS diagnosis. The
events were defined as death or lung TPL, and O2therapy. The median pre-event period for PFTs in all subjects was 24.0
months (interquartile range [IQR] 7.5-24.0 months) (E-table 1).
Figure 1 illustrates the comparison of lung function during the study
period between Group 1 versus Group 2 and Group 3 versus Group 4.
FEV1% pred, FVC%, pred, and FEF25-75%
pred were lower in Group 1 than in Group 2 at all time points after BOS
diagnosis. However, these differences were significant at only the 6, 9,
and 18 month time points for FEV1% pred and the 9 month
time point for FEF25-75% pred after BOS diagnosis (allP <0.05, Figure 1a, E-table 3a). When comparing Groups 3
and 4, FEV1% pred and FVC% pred were significantly
lower in Group 3 than in Group 4 at 3 months post-BOS diagnosis and
afterward. The levels of FEF25-75% pred were also
significantly lower in Group 3 than in Group 4 at 3, 6, 9, 15, 18, and
21 months after BOS diagnosis (all P <0.05, Figure 1b,
E-table 3b).