Time at treatment of severe retinopathy of prematurity in China: Recommendations for guidelines in more mature infants

Abstract

Purpose To investigate the postmenstrual (PMA) age at treatment of severe retinopathy of prematurity (i.e. Type 1 prethreshold or threshold) in infants in a tertiary referral center in China. Principal Findings 76.6% (359/469) of infants were treated for threshold disease. 67.5%(317/469) of infants had a birth weight (BW) of 1250g or above and almost 30% (126) had a gestational age (GA) of 32 weeks or above. There was little difference in the characteristics of infants treated for Type 1 prethreshold or threshold ROP. After controlling for GA, PMA age at treatment was highest in infants with BW -≥2000g (mean PMA 40.3±4.4 weeks, p<0.001); after controlling for BW, higher GA was associated with higher PMA at treatment (mean PMA 41.5 weeks for gestational age >34 weeks, p <0.001). For every three weeks increase in GA there was a two-week increase in PMA at treatment (R2 = 0.20, p<0.001). The time at treatment of Type 1 prethreshold disease was similar to that for threshold disease i.e. chronological age 5.6 -7.4 weeks, or PMA 34.1-40.2 weeks but the lower end of the 95% confidence interval for chronological age for Type 1 prethreshold disease among infants with BW ≥-2000g was 3.7 weeks (i.e. before the recommended interval of 4-6 weeks after birth). Significance The Chinese guidelines regarding timing of the first examination are appropriate for infants with BW <2000g, but more mature infants should be examined a little earlier, at 3 weeks after birth, in order to detect Type 1 prethreshold disease which has a better prognosis than threshold.