The Colorado-retinopathy of prematurity model (CO-ROP): postnatal weight gain screening algorithm.

Purpose: To describe a novel retinopathy of prematurity (ROP) screening model incorporating birth weight, gestational age, and postnatal weight gain that maintains sensitivity but improves specificity in detecting all grades of ROP compared to current 2013 screening guidelines.

Methods: The medical records of 499 neonates from a single tertiary referral center who met the 2013 screening guidelines for ROP were retrospectively reviewed. Weekly weights were analyzed using standard logistic regression to determine the age at which the weekly net weight gain best predicted the development of ROP, which was designated as the postnatal weight gain criterion. The 2013 birth weight and gestational age criteria were included in an "and" fashion to form the CO-ROP model. Sensitivities and specificities in detecting high grade (type 1 and 2) and all grades of ROP were calculated.

Results: The CO-ROP model screens infants with a gestational age at birth of ≤30 weeks and birth weight of ≤1500 g and net weight gain of ≤650 g between birth and 1 month of age. In our cohort, CO-ROP had a sensitivity of 100% (95% CI, 92.1%-100.0%) for high-grade (type 1 and 2) ROP and 96.4% (95% CI, 92.3%-98.7%) for all grades of ROP. It would reduce the number of infants screened by 23.7% compared to 2013 guidelines. Calibrating the model to detect only high-grade ROP would result in a 45.9% reduction in the total number of infants screened.

Conclusions: CO-ROP is a simple model that maintains a statistically similar sensitivity in detecting all grades of ROP while significantly reducing the total number of required ROP screenings compared to 2013 guidelines. The study had a small sample size but shows promise for future research and clinical efforts.