RACIAL VARIATION IN RETINOPATHY OF PREMATURITY

Objectives: To determine and compare the incidence of severe, vision-t hreatening retinopathy of prematurity (ROP) in black and white low-bir th-weight infants. Design: Prospective cohort study. Setting: Seventy neonatal intensive care units in 23 US participating centers in the Mu lticenter Trial of Cryotherapy for Retinopathy of Prematurity. Patient s: A total of 4099 premature infants weighing less than 1251 g at birt h were enrolled to evaluate the natural history of ROP. This 'Natural History' cohort included 2158 white infants and 1584 black infants who were followed up prospectively according to a Natural History protoco l. Main Outcome Measures: Incidence and severity of acute ROP. Results : While ROP occurred with similar frequency in all racial subgroups, s evere ROP was less common in black infants. One hundred sixty (7.4%) o f 2158 white infants reached threshold ROP (defined as at least 5 cont iguous or 8 cumulative clock-hours of stage 3 retinopathy in zone 1 or zone 2 in the presence of ''plus disease'' [dilation and tortuosity o f the posterior pole blood vessels]), but only 51 (3.2%) of 1584 black infants progressed to threshold ROP. Using multiple logistic regressi on analysis, race emerged as a highly significant factor (P < .001) in the development of threshold disease, even when birth weight, gestati onal age status at delivery, sex, multiple births, and transport statu s were considered. Conclusions: Severe, vision-threatening ROP occurs with greater frequency in low-birth-weight white infants than in low-b irth-weight black infants who are seemingly at equivalent risk. The re ason for this disparity is unknown. We speculate that differences in r etinal pigmentation may confer relative protection against free radica l-mediated phototoxic injury in black infants.