Remission criteria for the follow-up of patients with acromegaly.
OBJECTIVE
The aim was to evaluate the validity of current remission criteria in acromegaly, a random GH level of <2.5 microg/l, a glucose-suppressed GH level of <1 microg/l and a normal IGF-I level.


METHODS
In forty-one patients treated for acromegaly (23 males and 18 females, 20-69 years) and 94 healthy subjects (50 males and 44 females, 20-78 years), basal GH and IGF-I levels and nadir GH levels after 75 g oral glucose were evaluated in decade blocks; these were assayed by sensitive immunoradiometric assays.


RESULTS
Basal GH levels varied widely from 0.022 to 10.4 in healthy subjects and were >2.5 microg/l in 19%. The mean post-glucose GH nadir was 0.067+/-0.009 microg/l (range 0.003-0.4 microg/l) and the upper limit of the GH nadir was 0.26 microg/l (means+2 S.D.) in healthy subjects. Thirty-five patients with acromegaly had high-for-age IGF-I levels in relation to our healthy subjects. In this group, 15 (42.9%) patients had basal GH levels of <2.5 microg/l, 14 (40%) patients had nadir GH levels of <1 microg/l, and three (8.6%) patients had GH suppression to <0.26 microg/l which was defined as normal GH suppression in our healthy subjects. Only six patients with acromegaly had normal-for-age IGF-I levels and all of these patients had basal GH levels of <2.5 microg/l and all but one had nadir GH levels of <0.26 microg/l.


CONCLUSIONS
A basal or random GH level of <2.5 microg/l is not a reliable criterion for remission in acromegaly and the currently accepted normal upper limit of 1 microg/l for post-glucose GH suppression is too high. Post-glucose nadir GH levels, measured with sensitive assays, can be <1.0 microg/l in 40% and basal GH levels can be <2.5 microg/l in 43% of the active acromegalic patients. IGF-I levels appeared to correlate better with a nadir GH cut-off of 0.26 microg/l rather than 1 microg/l in the determination of disease activity.
Gullu
Sevim
S
Department of Endocrinology and Metabolic Diseases, School of Medicine, Ankara University, 06100 Ankara, Turkey. sevim.gullu@temd.org.tr
Keles
Hatice
H
Delibasi
Tuncay
T
Tonyukuk
Vedia
V
Kamel
Nuri
N
Erdogan
Gurbuz
G
D000172:Acromegaly / Q000175:diagnosis* / Q000532:radiotherapy* / Q000601:surgery; D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D019382:Human Growth Hormone / Q000097:blood*; D006801:Humans; D015592:Immunoradiometric Assay / Q000592:standards; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D012074:Remission Induction; D015203:Reproducibility of Results; D012720:Severity of Illness Index
D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I