ESPE Abstracts

Background and Aim: Priming with sex steroids before growth hormone (GH) stimulation tests is considered to increase the specificity of the GH stimulation tests, however, its use in the diagnosis of growth hormone deficiency (GHD) is still controversial. Purpose of this study is to analyze efficacy of sex steroid priming in the diagnosis of GHD.

Methods: The study comprised 115 peripubertal boys who were diagnosed with isolated GHD as a result of inadequate GH response in two GH stimulation tests (L-dopa and clonidine). Bone ages of all patients were ≥ 9 years, pubertal stages were either Tanner 1 (54/115, 47%) or Tanner 2 (61/115, 53%), and testosterone levels were <200 ng/dl in all patients. Sixty (52.2%) of these patients were primed with sex steroids (125 mg sustanon intramuscularly) one week before at least one of the two GH stimulation tests during the diagnosis of GHD. GH treatment at a dose of 0.033 mg/kg/day was started in all patients and GH stimulation tests were repeated in the first year of treatment. Clinical, auxological, laboratory characteristics, annual growth velocity and annual change in bone age during GH treatment were compared between patients with and without sex steroid priming, among those with a peak GH response <10 ng/ml during the retest.

Results: At diagnosis of GHD mean age was 12.8±2.6 years (10.1-16.2). Chronological and bone age, height-SDS, peak GH, IGF1 and IGFBP3 levels at diagnosis, as well as target height SDS were similar between those who were primed vs not primed. At retest (one year of GH therapy) peak GH during the retest was <10 ng/ml in 70% (42/60) of the patients primed with sex steroids, and in 47.3% (26/55) of those who were not primed (P<0.001). Under GH treatment, the annual change in height SDS of the primed group was higher than the unprimed group (0.7±0.3 vs 0.5±0.3, P<0.001). In addition, the annual progression of bone age in the sex steroid-primed group during GH treatment was slower in comparison to the unprimed group (1.0±0.3 years vs 1.6±0.4 years, P<0.001).

Conclusion: Individuals diagnosed with GHD by GH stimulation test under priming with sex steroids have better height gain and a higher probability of a diagnosis of GHD in the repeat test. In other words, priming with sex steroids increases the specificity of the GH stimulation test in identifying GHD.