Unconjugated bilirubin is correlated with the severeness and neurodevelopmental outcomes in neonatal hypoxic-ischemic encephalopathy

Abstract

Unconjugated bilirubin (UB) levels during the first week after birth are related to outcomes in neonatal hypoxic-ischemic encephalopathy (HIE). Clinical Sarnat staging of HIE, brain magnetic resonance imaging (MRI), hearing outcomes, and neurodevelopmental outcomes ≥ 1 year were used to correlate UB in 82 HIE patients. The initial UB level was significantly correlated with lactic acid levels. The peak UB was higher (p < 0.001) in stage I (10.13 ± 4.03 mg/dL, n = 34) than in stages II and III (6.11 ± 2.88 mg/dL, n = 48). Among the 48 patients receiving hypothermia treatment, a higher peak UB was significantly (p < 0.001) correlated with unremarkable brain MRI scans and unremarkable neurodevelopmental outcomes at age ≥ 1 year. The peak UB were higher (P = 0.015) in patients free of seizures until 1 year of age (6.63 ± 2.91 mg/dL) than in patients with seizures (4.17 ± 1.77 mg/dL). Regarding hearing outcomes, there were no significant differences between patients with and without hearing loss. The UB level in the first week after birth is an important biomarker for clinical staging, MRI findings, seizures after discharge before 1 year of age, and neurodevelopmental outcomes at ≥ 1 year of age.

Figure 1

Flow chart of the 102 neonatal patients with HIE. MRI, magnetic resonance imaging.

Figure 2

UB levels on first day was to correlate the clinical staging and systemic blood biomarkers for HIE. (A) clinical staging vs UB. The peak UB level was negatively correlated (P = 0.002) with the clinical staging. (B) lactic acid vs UB. Spearman's Rho calculator exhibited [Y (lactic acid) =  − 4.71X (UB) + 80.47] (r_s) =  − 0.35; p = 0.005. (C) LDH vs UB. The first UB and LDH correlation was [ŷ (LDH) =  − 32.42X (UB) + 1015.6) (r_s = 0.092, p = 0.479)]. (D) SGOT vs UB. The first UB and GOT exhibited [ŷ =  − 7.83X + 155.6 (r_s = 0.077, p = 0.594). (E) SGPT vs UB. The first UB and SGPT correlation exhibited [ŷ (GPT) =  − 4.59X (UB) + 51.69 by Spearman's Rho calculator (r_s = − 0.082, 0.082, p = 0.570).