Serum KL-6 as an Early Predictor of Bronchopulmonary Dysplasia in Preterm Neonates: A Prospective Cohort Study

Bronchopulmonary dysplasia (BPD) is a major respiratory morbidity in preterm infants. Early recognition of neonates at risk is essential to guide management and improve prognosis. Serum Krebs von den Lungen-6 (KL-6), has been identified as a promising marker of alveolar epithelial injury. This study evaluated the diagnostic, prognostic and predictive value of serum KL-6 levels for BPD development in preterm neonates and examined their association with clinical and neonatal characteristics.

A prospective cohort study was conducted on sixty-five preterm infants, of whom sixty-two completed follow-up and were included in the final analysis. preterm infants ≤32 weeks gestation and ≤1500 g birth weight admitted to the Neonatal Intensive Care Unit at Demerdash Hospital, Ain Shams University, Egypt. Serum KL-6 levels were measured on postnatal Days 7 and 14 using enzyme-linked immunosorbent assay (ELISA). Clinical and perinatal data, including ventilation duration, oxygen therapy and hospitalization length, were recorded. BPD diagnosis followed the National Institute of Child Health and Human Development (NICHD) criteria.

Neonates who developed BPD exhibited significantly elevated KL-6 levels on both Day 7 (p = 0.005) and Day 14 (p < 0.001), as compared to those who didn't develop BPD, respectively. Among BPD group; An optimal cutoff of 254 U/mL yielded 80.8% sensitivity and 80.6% specificity, on Day 14 evaluation. KL-6 correlated inversely with gestational age and birth weight, but positively with oxygen and ventilation duration. Persistently high KL-6 during the first two weeks strongly predicted BPD, suggesting that recurrent KL-6 assessment offers a valuable, non-invasive tool for early identification of at-risk preterm infants.