The effectiveness of arginine + GHRH test compared with GHRH + GHRP-6 test in diagnosing growth hormone deficiency in adults.
OBJECTIVE
The objective of this study is to investigate the performance of two novel tests in diagnosing growth hormone deficiency in adults.


METHODS
Fifty patients presenting with long-standing hypopituitarism and two control groups consisting of 50 healthy subjects in each group [age-, sex- and body mass index (BMI)-matched] participated in a multicentre study. All underwent two provocative tests on different days within 3 months apart: (i) a combined GHRH + GHRP-6 test and (ii) arginine + GHRH test. Main outcome measures were sensitivity, specificity and areas under receiver operating characteristic curves (ROC) for GHRH + GHRP-6 and arginine + GHRH tests in the diagnosis of GH deficiency in adults.


RESULTS
A peak GH level after GHRH + GHRP-6, under 15.0 microg/l had a sensitivity of 94.4% and specificity of 98.8% for diagnosing GHD and area under the ROC curve was 0.99 (95% confidence interval 0.95-0.99). For peak GH levels after arginine + GHRH, a level under 9.6 microg/l had a sensitivity of 88.4% and specificity of 95% and area under the ROC curve of 0.96 (95% confidence interval 0.91-0.98). The relationship between the increment in serum GH following GHRH + GHRP-6 and arginine + GHRH test was positive, i.e. r = 0.749, P = 0.001.Thus, there was high concordance between both tests.


CONCLUSIONS
Both GHRH + GHRP-6 and/or arginine + GHRH test may serve as an alternative to the ITT in diagnosing GHD in adults.
Popovic
Vera
V
Institute of Endocrinology, Diabetes and Diseases of Metabolism, University Clinical Center, Belgrade, Yugoslavia. popver@eunet.yu
Pekic
Sandra
S
Doknic
Mirjana
M
Micic
Dragan
D
Damjanovic
Svetozar
S
Zarkovic
Milos
M
Aimaretti
Gianluca
G
Corneli
Ginerva
G
Ghigo
Ezio
E
Deiguez
Carlos
C
Casanueva
Felipe F
FF
D000328:Adult; D000368:Aged; D001120:Arginine; D016022:Case-Control Studies; D005260:Female; D006130:Growth Disorders / Q000175:diagnosis*; D013006:Growth Hormone / Q000097:blood* / Q000172:deficiency*; D013007:Growth Hormone-Releasing Hormone; D006801:Humans; D008297:Male; D008875:Middle Aged; D009842:Oligopeptides; D011237:Predictive Value of Tests; D012372:ROC Curve; D012680:Sensitivity and Specificity
D009842:Oligopeptides; C041048:growth hormone releasing hexapeptide; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D001120:Arginine