Risk factors for severe retinopathy of prematurity in premature infants: a single-center study.

Objective: To evaluate the incidence and risk factors for severe retinopathy of prematurity (ROP) in preterm infants.

Methods: Between May, 2008 and May, 2011, a total of 957 preterm infants at 4-6 weeks of chronological age or 32 weeks of postmenstrual age underwent retinal evaluation by RetCamII in our center, and the data of infants with ROP in any stage were analyzed.

Results: Among the 957 preterm infants, we found 86 (8.99%) infants to have ROP in different stages, including 60 (6.27%) with mild ROP and 26 (2.72%) with severe ROP. The birth weight and gestational age of the infants with severe ROP averaged 1 420.40∓328.64 g and 29.88∓1.67 weeks, as compared to 1 593.28∓339.30 g and 31.78∓2.53 weeks in those with mild ROP, respectively, showing a significant difference between the two groups (P<0.005). The significant variables for severe ROP included gestational age (P=0.001), birth weight (P=0.035), 1 min Apgar score (P=0.001), 5 min Apgar score (P=0.005), number of blood transfusions (P=0.032), and the presence of apnea (P=0.04) and retinal hemorrhage (P=0.000). Gestational age and retinal hemorrhage were the independent risk factors for severe ROP (OR=0.353, 95%CI 0.163-0.763, P=0.008; OR=26.133, 95%CI 3.042-224.501, P=0.035).

Conclusion: Severe ROP tends to have a decreasing incidence and occurs more often in more mature preterm infants. The affected infants have the characteristics of the first epidemics. Gestational age and retinal hemorrhage are independent predictive factors for severe ROP.