Growth Hormone Deficiency: Permanence and Diagnosis in Young Adults

Objective: To optimize the tools for diagnosing idiopathic growth hormone (GH) deficiency. Methods: We compared the data of 43 young adults treated for GH deficiency before and after GH treatment and puberty. Those with organic lesions were assigned to group 1 (n = 9), those with certain GH deficiency (n = 11) to group 2 and those with no criterion of certitude of GH deficiency to group 3 (n = 23). Results: Group 1 patients: the GH peaks at first [1.5 ± (SE) 0.4 µg/l] and second (1.9 ± 0.7 µg/l) evaluations before treatment were similar to those at the third evaluation (1.2 ± 0.8 µg/l) after treatment. Group 2 patients: they had similar peaks (2.6 ± 0.8, 2.9 ± 0.5 and 5.5 ± 1.4 µg/l). Group 3 patients: the peaks increased from 4.9 ± 0.4 and 4.8 ± 0.4 to 18.4 ± 2.3 µg/l (p < 0.0001); 87% had a GH peak >10 µg/l at this evaluation. The plasma insulin-like growth factor 1 was initially below –2 z-score in 12/13 of these patients and similarly low in 4/17 patients at the third evaluation. The growth rates of the three groups before and their increase during the 1st year of treatment were similar. Conclusion: Almost all patients with GH deficiency before puberty without criteria of certitude had a normal GH peak after puberty. Some of these patients probably had a transiently low GH secretion.