Relationship of retinopathy of prematurity with trajectory of hemoglobin, anemia and blood transfusion in very premature/very low birth weight neonates: a repeated measurement analysis

Abstract Purpose : To investigate the effects of trajectory of hemoglobin and duration of anemia over the first 5 weeks of life on risk of retinopathy of prematurity (ROP).Methods: We enrolled 465 premature infants with <32 gestational weeks or <1500g. Logistic regression was performed to analyze associations between the risk of ROP and hemoglobin, anemia and the number of blood transfusions at each gestational week. Generalized estimating equation was used to analyze the association of ROP with repeated-measured hemoglobin, anemia and blood transfusions. Finally, the dose-response relationship between hemoglobin level during the first week and the risks of ROP were analyzed using restrictive cubic spline analysis.Results: ROP was associated with decreased hemoglobin concentrations [OR = 0.997, 95%CIs = 0.994～1.000), anemia (OR = 1.175, 95%CIs = 1.011～1.364) and increased numbers of blood transfusion (OR = 1.373, 95%CIs = 1.233～1.528). Compared to the high trajectory of hemoglobin, infants with low hemoglobin trajectory had high risk of ROP (OR = 1.553, 95%CIs = 1.040～2.320). The hemoglobin during the postnatal first week was associated with risk of ROP in a nonlinear manner. The risk of ROP was lowest when the concentration of hemoglobin was approximate 140g/L.Conclusions: Anemia and blood transfusion after birth were independent risk factors of ROP. Besides, the concentrations of hemoglobin during the first five weeks of life was associated with the risk of ROP, and should be controlled at 140g/L in premature neonates immediately.