Endocrine Abstracts

Due to its rarity, initial endocrine abnormalities in acromegaly are difficult to investigate in a large cohort, especially with respect to cofounding variables. We searched the German Acromegaly Register for data on the first presentation of patients with acromegaly.

Up to November 2005, 1485 patients with acromegaly had been entered into the database. Male patients demonstrated significantly higher random GH (21.0 (0.2–620.0) ng/ml, median (range)) and IGF-1 (773.0 (118–2000) ng/ml) levels than females with 14.0 (0.06–556.0) ng/ml (P<0.005) and 679.0 (136–2103) ng/ml (P<0.0001). Furthermore, comparison of biochemical parameters for various age decades demonstrated a significant association between increasing age and decreasing random GH and IGF-1 levels. Gonadal insufficiency occurred in 18.8%, secondary adrenal insufficiency in 11.8%, TSH deficiency in 7.5%, and diabetes insipidus in 1.3% of subjects. Pituitary insufficiencies occurred with higher frequency in male patients (39.1% vs. 22.0%, P<0.0001), and in a significantly higher percentage of patients with macro- (31.6%) compared to microadenomas (18.1%, P<0.005). During initial biochemical analysis, 6.4%, 1.5%, and 3.7% of subjects revealed non-pathological results for random GH (<2.5 ng/ml), minimal GH during oGTT (<1 ng/ml), and IGF-1, respectively. None had normal, and 91,4% had pathological results for all three parameters. Whereas the combination of GH during oGTT and IGF-1 raised suspicion of acromegaly in all subjects, 0.5% and 1.1% of subjects demonstrated normal values with combinations of random GH and IGF-1, or random and glucose suppressed GH, respectively.

In conclusion, biochemical activity of acromegaly may depend on age and sex. Therefore, therapy may need to consider and being adapted according to these parameters. Patients with acromegaly may need to be evaluated for pituitary insufficiencies, even with microadenomas. The combination of glucose-suppressed GH and IGF-1 may be the best screening parameters for acromegaly.