Abstract
Purpose :
Current United States screening guidelines for retinopathy of prematurity (ROP) recommend initiating examinations at 4 weeks after birth or 31 weeks postmenstrual age (PMA), whichever occurs later, in order to ensure timely diagnosis of disease requiring treatment (type 1 ROP). Therefore, exams begin at chronological age 4 to 9 weeks or at a PMA of 31 to 34 weeks, for infants born at gestational ages (GA) 22 to 30 weeks. To help inform scheduling of ROP examinations, we sought to determine the timing of developing type 1 ROP (in terms of both PMA and postnatal age) across GA groups, using data from two large ROP studies.
Methods :
We performed a secondary analysis of data from the North American G-ROP-1 (7483 infants from 29 hospitals, 2006-2012) and G-ROP-2 (3980 infants from 41 hospitals, 2015-2017) studies. PMA and postnatal age at first diagnosis of type 1 ROP were summarized using descriptive statistics and stratified by GA. The crude risks for type 1 ROP across PMA and postnatal age were calculated and plotted, stratified by GA.
Results :
Among 11,463 infants (mean birth weight 1095 grams, mean GA 28 weeks), 673 (5.9%) infants developed type 1 ROP. The type 1 ROP rate decreased with larger GA (28.8% for GA 23 weeks or less, 0.2% for GA 31-32 weeks) and no infants with GA after 32 weeks (n=440) developed type 1 ROP. The median PMA at type 1 ROP was 36 weeks (range 30-46), and increased with increasing GA (35 weeks for GA 22-24 weeks, 41 weeks for GA 29-30 weeks). The median postnatal age at type 1 ROP was 11 weeks (range 5-21) and was similar across GA 22 to 30 weeks. The peak risk for type 1 ROP occurred at postnatal weeks 11-12 regardless of GA (Figure 1), while the peak risk of type 1 ROP in terms of PMA varied more across GA’s (Figure 2). However, risk of type 1 ROP was present over a wide range in terms of both PMA and postnatal age (Figures 1, 2).
Conclusions :
The peak risk of type 1 ROP considered in terms of PMA varies more with GA than does the peak risk of type 1 ROP considered in terms of postnatal age. However, general clinical risk of type 1 ROP occurred over a wide time window in terms of both PMA and postnatal age. To prevent delayed treatment of type 1 ROP, clinicians should be aware of this wide variation in the timing of type 1 ROP regardless of whether chronological or developmental age are considered.
This is a 2020 ARVO Annual Meeting abstract.