Immaturity and Disease Severity are Independent Risk Factors to Develop Retinopathy of Prematurity

Purpose: Document indicators of an increased risk to develop retinopathy of prematurity (ROP) in low birth weight (LBW, < 1500g) infants. Methods: Retrospective chart review. Neonatal characteristics collected were birth weight, gestational age (GA), CRIB (Clinical Risk Index for Babies) score, Apgar score and indicators of respiratory, circulatory and renal instability. Small for gestational age (SGA, i.e. < 10 th percentile GA) was registered while postnatal growth was also recorded as a dichotomous variable, whether or not 150% of the birth weight was reached on day 42 of life. Results: On 284 LBW infants, 248 (87%) survived until discharge. ROP (any stage) was documented in 74 (30%) survivors of whom 41 (17%) developed stage 3 ROP. Incidence of stage 3 ROP in < 1000g and ROP in 1000-1250 birth weight cohorts was 42% and 16% respectively with almost absence of any ROP in neonates with a birth weight > 1 250g. In a logistic regression model in 248 LBW survivors, both GA (OR 0.42) and CRIB score (OR 1.35) remained independent risk factors for stage 3 ROP, resulting in 90% of cases classified correctly. Conclusions: Stage 3 ROP is almost exclusively limited to neonates with a birth weight below 1000g and retinopathy (any stage) is almost absent in neonates with a birth weight > 1 250g. Immaturity, i.e. GA at birth and CRIB score, reflecting disease severity, are the most important risk factors to develop retinopathy.