Abstract 1073 Poster Session IV, Tuesday, 5/4 (poster 285)

To investigate the relationship between adrenal function and CLD, we measured plasma cortisol (PC) during the first 28d of life for a subset of infants born at 5 of 13 centers in the North American TRH Collaborative Trial. Analyses were performed on 314 infants 24 to < 32 wk gestation whose mothers received 1 or 2 courses of antenatal corticosteroids plus TRH or placebo. Infants with plasma samples were similar to the total TRH study population with respect to gestational age and demographic characteristics. Median PC was 2.3 (range 0.1-17.9) µg/ml at birth, reached maximal levels at 24h (10.7, range 0.8-124.6), and decreased to 5.3 (range 0.2-24.7) µg/ml at 14-28d of age. The Clinical Risk Index for Babies (CRIB), a neonatal assessment tool with increased levels associated with increased risk of mortality, was positively correlated with PC level on day 1, 3-7, and 14-28. PC was not associated with TRH vs. placebo treatment at any time point. To examine the relationship between PC and adverse outcome of death or CLD at 36wk postmenstrual age - (CLD36), logistic regression models adjusting for known contributing clinical factors (gestational age and CRIB score) were fit. There was a borderline negative association between median PC level at 3-7d and CLD36 (p=0.08). After adjusting for gestational age and CRIB score, the predicted probability of CLD36 was only minimally influenced by PC level at 3-7d (figure).

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We conclude that there is a borderline statistical association between CLD36 and PC levels in the first week of life, but the magnitude of this effect is small. Possible benefits/risks of replacement cortisol will require randomized trials in infants with high CRIB scores and low PC levels or evidence of poor adrenal response to stress.