RESUMEN
OBJECTIVE: Bilirubin is a potent in vitro antioxidant. Despite repeated study, its in vivo significance has yet to be defined. Bilirubin is universally elevated in very low birthweight (VLBW) infants. Retinopathy of prematurity (ROP) is a disease thought to be associated with exposure to oxygen free radicals in VLBW infants. The objective of this study was to determine whether there was an association between peak bilirubin levels and ROP. METHODS: The risk for ROP, stages III and IV was measured as a function of increasing peak bilirubin levels in VLBW infants admitted to the neonatal ICU. A similar analysis was performed on a subgroup of VLBW infants with prolonged (> or =28 days) oxygen requirement. The relation between peak bilirubin level and the duration of oxygen requirement was tested by logistic regression analysis. All analyses were conducted after controlling for birthweight and presence of intraventricular hemorrhage (IVH). RESULTS: There was an increased risk for ROP, stages III and IV (OR 1.187; 95% CI 1.013 to 1.390; p=0.034) with elevated peak serum bilirubin levels in the entire population. Duration of oxygen requirement was not related to peak bilirubin (p>0.1). In the subgroup of infants with prolonged oxygen requirement (> or =28 days), there was no association between peak serum bilirubin levels and ROP III and IV (p>0.1); however, there was an association with further increased duration of oxygen requirement (p=0.034). CONCLUSION: Elevated peak bilirubin does not protect from and may be a risk for ROP in VLBW infants.