NCT04066569

Reproducibility and Utility of OGTT in Acromegaly

Reproducibility and Utility of Growth Hormone Inhibition by Oral Glucose Tolerance Test for the Diagnosis of Acromegaly

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 109 (actual)
• Sponsor: Assistance Publique - Hôpitaux de Paris · Academic / Other
• Sex: All
• Age: 18 Years – 85 Years
• Healthy volunteers: Accepted

Summary

Prospective study of reproducibility and utility of growth hormone inhibition by oral glucose tolerance test for the diagnosis of acromegaly, in acromegalic and non-acromegalic subjects, with a randomized double-blind crossover over placebo arm in the group of acromegalic patients

Detailed description

Rational: The initial step of biological diagnosis of acromegaly is based on assessment of IGF-I. According to current recommendations, the diagnosis must be confirmed by an oral glucose tolerance test (OGTT) to show that there is no growth hormone (GH) decrease lower than 1 μg/L (Katznelson , et al., 2014). Reproducibility of GH suppression by the OGTT has never been evaluated in either acromegalic or healthy subjects, although it is essential to determine the reliability of this test. Spontaneous fluctuations in GH in acromegaly could significantly influence the response of GH to the OGTT and cause low reproducibility of the test in this population. In particular, this reliability could be different according to the typical or moderate clinical presentation because of the persistence of a residual ultradian rhythm of GH secretion. The usefulness of oral glucose loading and the resulting hyperglycemia (which may limit GH secretion) has never been compared to an appropriate placebo (aspartame, at a dose equivalent to 75 g glucose), which does not cause hyperglycemia. Ingestion of 75 g of glucose is often responsible for nausea and vomiting. More rarely, the drop in blood glucose reactive to hyper insulinemia at the end of the test, can be the cause of discomfort. Primary objective: To determine the reproducibility of the GH response to OGTT in acromegaly by studying, in subjects with acromegaly, changes in GH concentration within 2 hours after oral administration of 75 g of glucose at 2 repeated tests in the same subject. Secondary objectives: 1. To analyze the reproducibility of the GH response to the OGTT as a function of the severity of acromegaly ("typical" form, "intermediate" form of acromegaly) and in a group of non-acromegalic subjects. 2. To evaluate the diagnostic value (utility) of OGTT in acromegaly by comparing, in subjects with acromegaly, the response of GH to oral administration of 75 g of glucose (OGTT) and 375 mg of aspartame (placebo). 3. Evaluate OGTT-stimulated insulin secretion in acromegalic and non-acromegalic subjects.

Conditions

• Acromegaly

Interventions

Type	Name	Description
OTHER	Performed 3 diagnostic tests (2 OGTT tests with 75 g of Glucose and 1 placebo test with 375 mg of Aspartam	After inclusion, the study will include the sequential realization of 3 dynamic GH secretion tests, separated by a period of 24 hours to 30 days. Each subject will have two OGTT tests (oral administration of 75 g of glucose in 200 mL of water) and a placebo test (oral administration of 375 mg of aspartame in 200 mL of water). The order of the three tests (2 OGTT and 1 placebo) in acromegalic patients will be randomized. The tests will be performed under the same conditions
OTHER	Performed 2 diagnostic tests (2 OGTT tests with 75g of Glucose)	After inclusion, the study will include the sequential realization of 2 dynamic GH secretion tests, separated by a period of 24 hours to 30 days. Each subject will have two OGTT tests (oral administration of 75 g of glucose in 200 mL of water). The tests will be performed under the same conditions (fasting, semi-recumbent position, start of the test at 9 am) and will include a measurement of blood glucose, GH, insulinemia at -15, 0, 30, 60, 90, 120 min after ingestion of glucose or placebo.

Timeline

• Start date: 2020-08-24
• Primary completion: 2024-10-30
• Completion: 2025-03-05
• First posted: 2019-08-26
• Last updated: 2025-11-24

Locations

1 site across 1 country: France