Consensus and controversies about diagnosing GH deficiency: a Delphi survey by the GH research society

Purpose: Biochemical tests are required for diagnosing GH-deficiency in children and adults, but controversies remain regarding diagnostic criteria and type of biochemical tests. The aim of the study is to map the clinical practices of GHD diagnosis in children and adults. Methods: The Growth Hormone Research Society members initiated a Delphi survey of the diagnosis of GHD in children and adults. Pediatric (n = 18) and adult (n = 25) endocrinologists from 14 countries participated and rated their extent of agreement with 61 statements using a Likert-type-scale (1–7). Consensus was predefined as ≥ 80% of panelists rating their agreement unidirectionally as either ≥ 5 (agreement) or ≤ 3 (disagreement). Results: The pediatric panel reached consensus on 17 of 29 (59%) statements on diagnosis in children, whereas the adult panel reached consensus on 28 of 32 (88%) statements on adult patients. There was general agreement to test for GHD in an appropriate clinical context and also on the timing of testing for GHD in both children and adults. A subnormal IGF-I level was considered diagnostic in both children and adults with panhypopituitarism. In children, there was consensus to recommend the arginine stimulation test and the glucagon test. The insulin tolerance test (ITT) was considered gold standard in adults and there was also consensus to recommend the macimorelin test. A stimulated GH cut-off < 5μg/l was consistent with severe GHD in children, whereas test-specific cut-offs were recommended in adults. Conclusion: Consensus on the GHD diagnosis was lower in pediatric practice, mainly with respect to choice and interpretation of GH stimulation tests.