ESPE Abstracts

While it has been established that within the first 4 months of life there is an absence of the circadian rhythm guiding cortisol secretion, it remains unclear if a random serum cortisol (rSC) level is useful in diagnosing neonatal primary adrenal insufficiency (PAI). The objective of this study is to determine the utility of rSC in determining PAI within the first 4 months of life. This is a retrospective chart review of subjects who had rSC collection and high dose cosyntropin stimulation test (HDT) prior to 4 months of life. Indications for performing HDT were: genital ambiguity, hypoglycemia, hypotension and other, which included abnormal newborn screen for congenital adrenal hyperplasia (CAH). Subjects who were deceased, received medications such as opioids, ketoconazole, or steroids (inhaled or oral within 48 hrs of obtaining rSC), or had missing data points were excluded from analysis. Baseline laboratory measurements, including rSC levels, were recorded and the cohort was divided into 2 groups: those with PAI, defined as peak stimulated cortisol levels < 15.5 mg/dL and a clinical diagnosis associated with this such as CAH or adrenal hemorrhage, and a non-PAI group of subjects with normal peak cortisol levels (≥15.5 mg/dl). rSC levels were compared between the groups using unpaired, two-tailed t-test. P-values < 0.05 were considered significant. Receiver operator curve (ROC) analysis was used to identify the area under the curve (AUC) for the diagnosis of PAI. The study included 92 infants. Mean age and weight (±SDs) were 35.8±30.8 days and 3128.1 ± 1188.8 g, respectively, 41 (45%) preterm, 27 (29 %) females, and 7 (7.6%) had PAI. The most common indications for rSC testing were to assess for CAH (56%) and hypoglycemia (22%). During the first 4 months of life mean, rSC levels were for the PAI group (4.94 ± 4.39 mg/dL) vs non-PAI (6.13 ± 5.07 mg/dL) groups, P=0.55. ROC analysis for rSC in diagnosing PAI during the first 4 months vs first 28 days of life, showed AUC 0.5504 vs 0.6420, respectively. While rSC can be collected within the first 4 months of life, and there is marginal improvement in the AUC during the first 28 days of life when compared to the first 4 months of life, its diagnostic utility in determining PAI is quite limited. Based on this data if there’s a high index of suspicion for PAI, a stimulated cortisol level derived from HDT should be obtained.