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POSTNATAL SERUM INSULIN-LIKE GROWTH FACTOR I AND RETINOPATHY OF PREMATURITY

Purpose: Low serum IGF-1 has been associated with development of severe ROP, but no U.S. studies have been reported. We sought to determine the relationship between postnatal serum IGF-1 levels and severe ROP in a racially diverse U.S. cohort. Methods: Prospective cohort study of 74 infants with birth weight <1,251 g and a known ROP outcome at 3 Philadelphia hospitals. Weekly postnatal filter paper blood spot IGF-1 assays were measured through 42 weeks postmenstrual age. Results: The cohort included 20 white, 45 black, 2 Asian, and 9 other infants; median gestational age was 27.6 weeks (range 23–33 weeks), and median birth weight was 975 g (range 490–1,250 g). During postmenstrual age Weeks 28 to 33, mean IGF-1 was 20.0 ng/mL (standard error 0.52) for no ROP (n = 46), 18.0 (0.49) for Stage 1 or 2 (n = 23), and 17.0 (0.70) for Stage 3 (n = 5, 2 lasered) (P = 0.003). Adjustment for birth weight and gestational age showed similar results. Conclusion: The presence and timing of an association between low postnatal serum IGF and ROP in a racially diverse U.S. sample were found to be consistent with those of European cohorts. This association provides the pathophysiological basis for growth-based predictive models, which could improve efficiency of ROP screening.