Abstract
Purpose:
To determine baseline characteristics associated with risk for development of Zone I versus Zone II retinopathy of prematurity (ROP)
Methods:
ET-ROP data was obtained as an MS Access database which we decoded and transferred into Stata for analysis. Of the 401 patients randomized, 317 with bilateral disease had one eye randomized to early treatment, and 44 patients with asymmetric disease were randomized to early treatment. Of these 361 patients, we identified infants with Zone I versus Zone II disease. We defined an infant as having Zone I disease if they had any stage 2 or 3 in Zone I. We included stage 1 disease if they had no worse disease in Zone II. An infant with Zone II disease was defined as an infant who did not meet criteria for Zone I disease but had any stage, 1,2, or 3 in Zone II. Risk factors analyzed included birth weight (BW), gestational age (GA), sex, race, singleton vs. multiple birth, congenital anomalies, and inborn vs. transfer using univariate and multivariate analysis.
Results:
The mean GA and BW for infants with Zone I disease was 24.7 weeks and 665.6g and for those with Zone II disease was 25.4 weeks and 724.8g. (p value=0.0008 and 0.0001, respectively). In the initial multivariate analysis GA, BW and African American race were found to be statistically significant risk factors for the development of Zone I ROP. For every 100 g decrease in BW, the risk of developing Zone I disease increased by 30% (OR 1.30, 95% 1.10-1.54). African Americans (n=64) had a significantly higher risk of developing Zone I ROP (OR=3.78, CI 2.06-6.96, p<0.001) compared to Caucasian patients (n=230) when controlling for all other variables.
Conclusions:
In the ET-ROP study, BW was a significant risk factor for the development of Zone I ROP. Data from CRYO-ROP suggested African American patients are less likely to develop severe ROP. This re-analysis of ET-ROP suggests that African Americans have a higher risk of developing Zone I ROP than Zone II ROP. when controlling for birth weight and other baseline characteristics.
Keywords: 706 retinopathy of prematurity •
464 clinical (human) or epidemiologic studies: risk factor assessment