The goal of this study was to evaluate urinary N-terminal fragment of B-type natriuretic peptide concentrations, normalized to creatinine (UNBCR), to predict morbidities at discharge in preterm infants.
UNBCR were determined in urine collected on day of life (DOL) 2, 7, 14, and 28 in 136 preterm infants <1500 g birth weight, 22 of whom developed bronchopulmonary dysplasia (BPD), defined as oxygen supplementation at 36 weeks' gestational age) and 11 infants developed severe retinopathy (ROP), defined as stage 3 or stage ≥2 requiring surgery).
UNBCR on DOL 7, 14, and 28 was elevated in infants who developed BPD or ROP compared with controls (P ≤ .001). On multiple regression analysis including birth weight and gestational age, ROP but not BPD remained independently associated with UNBCR on DOL 14 and 28. Areas under receiver operating characteristic curves for UNBCR on DOL 14 and 28 to predict ROP were 0.938 (0.027) and 0.954 (0.021), respectively. UNBCR DOL 14 and 28 thresholds exceeded by all infants with severe ROP (100% sensitivity, 100% negative predictive value) had a specificity of 66% and 85%, respectively.
UNBCR might hold promise to reduce unnecessary eye examinations by timely and accurate identification of infants at risk of severe ROP.