Retinopathy of prematurity: any difference in risk factors between a high and low risk population?

PURPOSE To document incidence of and risk factors for development of retinopathy of prematurity (ROP) in a population of low birthweight infants (< 1500 g). METHODS The authors registered clinical characteristics (birthweight, gestational age (GA), Clinical Risk Index for Babies (CRIB), Apgar score, respiratory characteristics (intubation, ventilation, respiratory support, supplemental oxygen, oxygenation index), prescription of dopamine, and maximal creatinemia) by retrospective chart review in two consecutive CRIB score-based (< 851 g, 851-1350 g) categories. Chi square and Mann-Whitney U tests were used to compare clinical characteristics in both categories and a stepwise logistic regression was done to document independent risk factors for either stage 3 (< 851 g) or any grade of ROP (851-1350 g). RESULTS Incidence of ROP was 65/157 (41%; 76% in < 851 g and 22% in 851-1350 g). Incidence of stage 3 ROP was 25/46 (54%) in the < 851 g and 4/84 (5%) in the 851-1350 g group. Among other risk factors, maximal creatinemia was a risk factor in the 851-1350 g cohort (p < 0.03). In a logistic regression model, only GA (OR 0.42) remained significant in the lowest birthweight category; in the 851-1350 g cohort, GA (OR 0.53) and CRIB score (OR 1.7) were independent risk factors for ROP. CONCLUSIONS In relatively more mature infants (851-1350 g), the risk to develop ROP is based on GA and on neonatal severity of disease (CRIB score); in the tiniest infants, GA is the most important risk factor. Microangiopathy might explain the association of maximal creatinemia and the risk of developing ROP.