Hemoglobin Levels on Day 3 of Life as Early Predictors of Bronchopulmonary Dysplasia in Preterm Infants

Backgrounds: Bronchopulmonary dysplasia (BPD) is a major contributor to mortality in extremely preterm infants. Therefore, it is essential to identify effective clinical prognostic indicators of BPD and implement early interventions. The objective of this study was to evaluate the predictive value of erythrocyte-related indices, such as hemoglobin (Hb) and hematocrit (Hct), for BPD. Methods: This retrospective cohort study included 413 neonates with a gestational age (GA) of < 32 weeks who were admitted to The First Affiliated Hospital of Wenzhou Medical University between January 2019 and January 2024. Maternal and infant characteristics were recorded, and Hb and Hct levels were measured on days 1, 3, 14 and 28 of life (DOL1, DOL3, DOL14, and DOL28, respectively). Results: Compared to non-BPD patients (n = 170), BPD patients (n = 218) had a lower GA (p < 0.001), birth weight (p < 0.001), 1-minute postnatal Apgar scores (p < 0.001) and 5-minute postnatal Apgar scores (p < 0.001). However, they exhibited higher rates of intubation in the delivery room (p < 0.001), surfactant treatment (p < 0.001), diuretic treatment (p < 0.001), caffeine treatment (p < 0.001), postnatal steroid use (p < 0.001), hemodynamically significant patent ductus arteriosus (hsPDA) (p < 0.001), intraventricular hemorrhage (IVH) (p = 0.001), retinopathy of prematurity (ROP) (p < 0.001), duration of invasive mechanical ventilation (IMV) ≥1 week (p < 0.001), and number of packed red blood cell (PRBC) transfusions (p < 0.001). In addition, BPD patients received PRBC transfusions earlier (p = 0.004), had lower Hb levels on DOL1 (p = 0.001), DOL3 (p < 0.001) and DOL14 (p < 0.001), but higher levels on DOL28 (p = 0.003). They also had lower Hct levels on DOL1 (p = 0.004), DOL3 (p < 0.001) and DOL14 (p < 0.001), but higher levels on DOL28 (p = 0.001). An Hb level of ≤150 g/L on DOL3 (DOL3-Hb) was an early predictor for BPD (adjusted odds ratio (OR) = 3.222, p = 0.002), with high sensitivity (69.72%) and specificity (78.24%). The number of PRBC transfusions was also a significant risk factor for BPD (adjusted OR = 4.436, p < 0.001). Conclusions: Significant predictors of BPD included DOL3-Hb 150 g/L and the number of PRBC transfusions, with DOL3-Hb serving as an early predictor.