369 - A fragile start: defining early post-NICU-discharge symptom clusters in infants with bronchopulmonary dysplasia

Publication Number: 1353.369

William J. Scott, Medical College of Wisconsin, Milwaukee, WI, United States; Margaret E. Malnory, Medical College of Wisconsin, Wauwatosa, WI, United States; Kathryn EK. Berlin, Medical College of Wisconsin, Milwaukee, WI, United States; Rebecca Steuart, Medical College of Wisconsin, Milwaukee, WI, United States; Sara Dawson, Medical College of Wisconsin, Milwaukee, WI, United States; Joanne Lagatta, Medical College of Wisconsin, Milwaukee, WI, United States

Background: Respiratory symptoms for infants with BPD after NICU discharge are often assessed using asthma questionnaires. Yet studies found that 14% of infants requiring acute respiratory care reported no symptoms on asthma scales. Respiratory symptoms may differ between BPD and asthma.

Objective: To identify respiratory symptom clusters during the first year post-NICU discharge in infants with BPD, and to explore associations between neonatal risk factors and these respiratory symptoms. We hypothesized that BPD severity was associated with an early "Respiratory Fragility" cluster (hypoxia, tachypnea, increased work of breathing [WOB]) , distinct from traditionally assessed symptoms of cough and wheezing.

Design/Methods: Single-center retrospective cohort study of infants with BPD ( < 32 weeks GA, respiratory support at 36 weeks PMA) discharged between July 2019-October 2025, including patients with tracheostomy, from our tertiary referral center. We developed an a priori symptom list based on qualitative interviews with clinicians and parents. Informed by a pilot manual chart review, we filtered encounters in an administrative database by type and specialty and manually reviewed documented symptom data. Tetrachoric correlation and hierarchical clustering were used for exploratory symptom cluster analysis. Bivariate analyses assessed associations between neonatal risk factors and symptoms in the first year. This study was declared exempt by the Children's Wisconsin institutional review board.

Results: The cohort (n=93) with 2,080 encounters had a median GA of 26 weeks (IQR 25-29) and birthweight of 870g (IQR 725-1110g); 57% had Grade 2 BPD, and 78% were discharged using home oxygen . Median encounter follow-up for this cohort was 11 months (IQR 8-12). Symptoms of WOB, hypoxia, and tachypnea peaked within the first 1-3 months post-discharge and decreased thereafter, while wheezing was infrequent in the first year (Figure 1). We found positive correlations (ρ ≈ 0.3-0.6) among tachypnea, cyanosis, apnea, and hypoxia (Figure 2). BPD severity (p=0.014-0.030) and home respiratory support at discharge (p=0.008-0.032) were significantly associated with the presence of hypoxia, tachypnea, and WOB during the first year, but not with wheezing (p>0.1) (Table 1).

Conclusion(s): We identified an early "Respiratory Fragility" symptom cluster of tachypnea, cyanosis and hypoxia in infants with BPD, peaking early post-NICU discharge and associated with BPD severity. These symptoms are not captured by current asthma questionnaires, supporting the need for BPD-specific symptom measures.

Raw Symptom Count by each post-NICU discharge month
The raw symptom counts across all encounters by each month following NICU discharge. Work of breathing, hypoxia, and tachypnea showed peaks within the first 1-3 months following discharge before dissipating over time. Wheeze was infrequently reported during the first NICU discharge year.

Symptom Tetrachoric Correlation arranged by Hierarchical Clustering
Tetrachoric correlation matrix with y- and x-axis ordering determined through hierarchical clustering with complete linkage. Work of breathing, tachypnea, cyanosis, apnea, and hypoxia grouped together through this clustering with Pearson correlates between 0.40 to 0.64. Wheeze and activity limitation grouped together with correlate of 0.40. Cough exhibited weaker correlation with wheeze at 0.29, however the association was statistically significant with p < 0.001.

NICU illness and discharge factor association with respiratory symptoms