Background: Reevaluation of children diagnosed as GH deficiency (GHD) showed 2575% of cases had normal GH responses in retests after cessation of therapy. Low reproducibility and high intra-individual variability of the tests are the important problems in diagnosis. Repeat evaluation during treatment may help detect cases with normal GH status earlier.
Objective and hypotheses: We repeated stimulation tests following the first year of GH treatment to detect patients with normal responses, and analyzed clinical and laboratory features in order to define the characteristic findings that may point to patients who require reassessment of GH status.
Method: One year after the onset of therapy, GH tests were repeated in 265 patients (MPHD 35.8%; isolated GHD-IGHD 64.2%). Auxological data, pubertal stage, IGF1, IGFBP3 levels, and imaging of the pituitary gland were analyzed. Final heights of cases with normal responses to retests in whom GH treatment was discontinued were recorded.
Results: Retests showed normal GH response in 40.6% of cases with IGHD. None of the patients with MPHD had a normal response during retest. Puberty or sex steroid priming in prepubertal cases increased the probability of normal response. GH response was normal in 45.6% of IGHD cases with normal pituitary MRI (68/149), and in 4.8% of IGHD cases with structural pituitary defects (1/21). The most important factors distinguishing normal and low responses were peak GH level at diagnosis and height gain in the first year of therapy. Cases with a peak GH <5 ng/ml, and height gain >0.61SDS are more likely to have permanent deficiency. In cases where GH was >10 ng/ml and therapy was discontinued, final heights were consistent with target heights.
Conclusion: Patients with MPHD do not need reevaluation for GH status. Patients with IGHD who have the following features should be reevaluated:
Peak GH >5 ng/ml at diagnosis.
Normal/hypoplastic pituitary gland.
Height gain <0.61SDS during the first year of therapy.
20 - 22 Sep 2014
European Society for Paediatric Endocrinology