Divergence between growth hormone and insulin-like growth factor-i concentrations in the follow-up of acromegaly.
BACKGROUND
Divergence between GH and IGF-I values is regularly observed in treated acromegalic patients, and its significance is unclear.


OBJECTIVE
The objective of the study was to explore the frequency and identify potential determinants of discordant serum GH and IGF-I concentrations in noncured acromegalic patients.


METHODS
Two hundred twenty-nine noncured acromegalic patients of the Belgian acromegaly registry (AcroBel) were grouped according to their mean GH level (< or = or > 2 microg/liter) and IGF-I z-score (< or = 2 or > 2). Clinical and metabolic parameters were compared between groups with active disease (high GH and IGF-I; n=81),high GH (with normal IGF-I; n=25), high IGF-I (with normal GH; n=55), and controlled disease (GH and IGF-I normal; n=68).


RESULTS
Compared with the high IGF-I group, the high GH group was characterized by younger age (52 vs. 58 yr, P < 0.05), female predominance (72 vs. 36%, P < 0.01), and lower body mass index (25 vs. 31 kg/m(2); P < 0.001), fasting glucose (91 vs. 99 mg/dl; P < 0.05), and glycated hemoglobin levels (5.7 vs. 6.1%; P < 0.01). There was no difference among the groups regarding baseline characteristics of pituitary adenoma, current medical treatment, or symptom score.


CONCLUSIONS
Thirty-five percent of noncured acromegalic patients exhibit a discordant GH and IGF-I pattern. The high GH phenotype was found predominantly in younger estrogen-sufficient females, implying a possible role for age, gender, and estrogens in this biochemical divergence. The high IGF-I phenotype was associated with a worse metabolic profile, suggesting that high IGF-I, rather than high GH, is indicative of persistently active disease.
Alexopoulou
Orsalia
O
Department of Endocrinology, St. Luc University Hospital, Université Catholique de Louvain, B-1200 Brussels, Belgium. orsalia.alexopoulou@diab.ucl.ac.be
Bex
Marie
M
Abs
Roger
R
T'Sjoen
Guy
G
Velkeniers
Brigitte
B
Maiter
Dominique
D
D000172:Acromegaly / Q000097:blood*; D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D002318:Cardiovascular Diseases / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000032:analysis; D019382:Human Growth Hormone / Q000097:blood*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors
D001786:Blood Glucose; D006442:Glycated Hemoglobin; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; C517652:hemoglobin A1c protein, human