ESPE Abstracts

Background: The growth hormone (GH) stimulation test, which requires multiple blood sampling, should be performed to confirm the diagnosis of growth hormone deficiency because of the pulsatile secretion of GH. In addition to hypoglycemia, L-dopa and arginine, deep sleep is also known as an important stimulator of GH secretion.

Objectives: The aim of study was to assess the accuracy and predictive value of the test of post-sleep GH secretion in diagnosing GHD, and compare with standard GH stimulation tests.

Methods: 100 cases of GH stimulation test were analyzed. GH stimulation was assessed in two standard stimulating tests. All individuals had short stature below the 3^rd percentile, and insulin-like growth factor (IGF)-1, IGF-BP3, peak GH levels at GH stimulation test, and post-sleep GH (1 hour after deep sleep) levels were measured. The difference between GH deficiency (GHD, n=63) and non-GHD (n=37) group was analyzed.

Results: The chronologic age, bone age, height standard deviation score (SDS) and IGF-1 SDS were not significant between GHD and non-GHD group. The post-sleep GH level was statistically significant (5.00 ± 3.63 ng/mL in GHD and 10.48 ± 6.72 ng/mL in non-GHD group) (P value < 0.001). Also, the post-sleep GH level was positively correlated with GH peak (r=0.47, P value < 0.001). Glucagon stimulation test showed the highest sensitivity (100%), specificity (100%), positive predictive value, negative predictive value among GH stimulation tests. The level of post-sleep GH above 6.95 ng/mL indicated non-GHD with 70.3 % sensitivity, 71.4 % specificity.

Conclusion: The post-sleep GH level could be used as an additive tool in the diagnosis of GHD. Glucagon was the most useful test among GH stimulation tests. Further investigation is required on the diagnostic criteria of GHD and predictors of response to GH treatment.