Comparison between weight gain and Fenton preterm growth z scores in assessing the risk of retinopathy of prematurity.

ABSTRACT

Several studies have shown that postnatal weight gain is a significant predictor for retinopathy of prematurity (ROP) in preterm infants. Using a cohort of 1,301 infants from a single-center ROP registry, we investigated whether incorporation of changes in Fenton preterm growth curve z scores (ie, deviation from the population average) provides improved predictive ability for developing ROP compared to weight gain alone. Three logistic regressions were fit to severe ROP (1) baseline model that included gestational age and birth weight, (2) the baseline model adding weight gain, and (3) the baseline model adding change in z score. The area under the receiver operating characteristic curve (C index) was used to compare models. Both weight gain and change in z scores were significant predictors after adjusting for birth weight (P = 0.01) and gestational age (P < 0.01). The C indices were not significantly improved by including weight gain or z score to the baseline model; however, for a subset of subjects, change in weight z score may be a more useful measure compared to simple weight gain with regards to assessing risk for severe ROP.