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Comparison of oral glucose tolerance test (OGTT) 100 g with OGTT 75 g for evaluation of acromegalic patients and the impact of gender on test reproducibility
Author(s) -
Arafat A. M.,
Müller L.,
Möhlig M.,
Mayr B.,
Kremenevskaya N.,
Pfeiffer A. F. H.,
Buchfelder M.,
Schöfl C.
Publication year - 2011
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.2011.04108.x
Subject(s) - acromegaly , medicine , endocrinology , glucose tolerance test , reproducibility , menstrual cycle , impaired glucose tolerance , insulin , hormone , insulin resistance , growth hormone , chemistry , chromatography
Summary Context Growth hormone (GH) measurements during an oral glucose tolerance test (OGTT) are essential for the diagnosis and follow‐up management of acromegaly. However, both 100 g glucose (OGTT 100 ) and 75 g glucose (OGTT 75 ) test variants are in clinical use. Whether the tests are interchangeable concerning GH nadir and test interpretation is unclear. Furthermore, information on test reproducibility and the impact of gender is scarce. Objective To compare both tests in acromegalic patients and to evaluate test reproducibility with respect to gender. Design, subjects and methods OGTT 100 and OGTT 75 were performed on two consecutive days in 54 acromegalic patients (46·9 ± 1·8 years, 30 women). OGTT 75 was repeated on three different occasions in 11 healthy men and 13 healthy women at different phases of the menstrual cycle. Results GH nadirs were comparable between tests [2·40 ± 0·52 (OGTT 100 ) and 2·46 ± 0·54 μg/l (OGTT 75 ); P = 0·356]. There were no differences at any time point in the mean values of GH, serum glucose or insulin between the two test variants. Test interpretation was highly consistent between the OGTT 100 and OGTT 75 [area under the receiver operated curve (ROC) = 0·995]. In men, GH, insulin and glucose measurements during OGTT 75 were highly reproducible. In women, however, basal and GH nadirs were significantly higher midcycle ( P < 0·05). Conclusions In acromegalic patients, there is no difference in GH nadirs and test interpretation after the ingestion of 100 g or 75 g glucose. The OGTT 75 is highly reproducible in men, but in women, it should be performed preferably in the early follicular phase.