Threshold retinopathy of prematurity in an urban hispanic population: The experience at LAC/USC medical center

Purpose. To determine the incidence and severity of threshold retinopathy of prematurity (ROP) in urban Hispanic patients served by an inner city public hospital. Methods. A retrospective chart review was performed on all infants discharged with birth weights ≤ 1500 grams born between January 1993 and December 1994 at the University of Southern California - Los Angeles County Medical Center. Of the 219 infants discharged, 165 patients (75%) were studied. Race, birthweight, gestational age, and most severe stage of ROP were recorded. Regular exams were done at 1 to 4 week intervals as dictated by the infants clinical status, beginning 4 to 6 weeks after birth. Results. One hundred sixty-five preterm Hispanic infants were retrospectively studied. The incidence of threshold ROP in this population was 11%(18/165). For those infants reaching threshold, the mean birthweight was 626 grams and the mean gestational age was 24.8 weeks. In those infants with favorable outcomes after laser therapy, the mean birthweight was 679 grams and the mean gestational age 25.8 weeks. In the group with unfavorable outcomes after laser therapy, the mean birthweight was 559 grams and the mean gestational age was 23.8 weeks. Overall, progression to threshold disease occurred on average 10.4 weeks after birth. Conclusions. This study examines the incidence and characteristics of threshold ROP in a predominately Hispanic inner city population. The observed incidence of 11% threshold ROP is significantly higher than that reported in the Cryo-ROP natural history data by Palmer et al. The significant risk factors noted in this study - low birth weight and short gestation - are well characterized and reported in other studies. Other factors that may contribute to this outcome will be examined.