Reassessment of the Growth Hormone Status in Young Adults with Childhood-Onset Growth Hormone Deficiency: Reappraisal of Insulin Tolerance Testing

Context: The 2007 Consensus Statement suggested a peak GH cutoff to insulin tolerance test (ITT) of less than 6 μg/liter in the diagnosis of permanent GH deficiency (GHD) in young adults with childhood-onset GHD (COGHD), although further validation was recommended. Objective: The aim of the study was to evaluate the accuracy of ITT, mean 12-h spontaneous nocturnal GH (SNGH), and IGF-I in the definition of permanent GHD. Design and Setting: The study was conducted in two Pediatric Endocrinology Centers. Patients and Methods: ITT, 12-h SNGH, and IGF-I were evaluated as single or combined tests in 79 subjects with COGHD (median age, 18.0 yr). The cohort consisted of 48 subjects with isolated GHD or one additional pituitary defect and normal MRI or anterior pituitary hypoplasia (group LLGHD, low likelihood GHD), and 31 subjects with structural hypothalamic-pituitary abnormalities or multiple pituitary hormone deficiencies (group HLGHD, high likelihood GHD). Results: Receiver operating characteristic analysis ...