Changes in Course of Retinopathy of Prematurity from 1986 to 2013: Comparison of Three Studies in the United States.

PURPOSE To compare infant and retinopathy of prematurity (ROP) characteristics from 3 clinical studies conducted over a 27-year period in the United States. DESIGN Secondary analysis of results of 3 clinical studies. PARTICIPANTS Infants with birth weight (BW) <1251 g. METHODS Analysis of data from the Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) and Early Treatment for Retinopathy of Prematurity (ETROP) trials and the primary data from the Telemedicine Approaches for the Evaluation of Acute-Phase Retinopathy of Prematurity (e-ROP) study. MAIN OUTCOME MEASURES Infant characteristics and onset, severity, and time course of ROP. RESULTS Across the 3 studies, mean (standard deviation) BW and mean gestational age (GA) decreased over time from CRYO-ROP (954 g [185 g], 27.9 weeks [2.2 weeks]) to ETROP (907 g [205 g], 27.4 weeks [2.2 weeks]) to e-ROP (864 g [212 g], 27.0 weeks [2.2 weeks]), with an increase in the percentage of infants enrolled weighing <750 g (15.8% CRYO, 24.9% ETROP, 33.4% e-ROP; P<0.0001). The percentage of infants who developed ROP varied only minimally (65.8% CRYO, 68.0% ETROP, 63.7% e-ROP; P = 0.003). Moderately severe ROP (defined as prethreshold or referral warranted) varied (17.8% CRYO, 12.3% ETROP, 19.4% e-ROP; P<0.0001), whereas the time of onset of any ROP did not vary (34.3 weeks CRYO, 34.1 weeks ETROP, 34.8 weeks e-ROP). CONCLUSIONS The BW and GA of infants enrolled in ROP studies in the United States have decreased over the past 27 years, whereas ROP prevalence and onset of disease are stable.