Defining growth hormone deficiency in adults

Area of Science:

• Endocrinology
• Metabolic Disorders
• Clinical Diagnostics

Background:

• Hyposomatotropism (growth hormone deficiency) lacks a distinct clinical syndrome in adults, necessitating reliable diagnostic strategies.
• Current methods for defining adult growth hormone deficiency lack consensus, with factors like aging and obesity complicating assessments.
• Accurate diagnosis is crucial for appropriate patient management and treatment.

Purpose of the Study:

• To evaluate the diagnostic accuracy of various tests for identifying organic growth hormone deficiency in adults.
• To compare the effectiveness of insulin-tolerance test (ITT), mean 24-hour GH concentration (IGHC), IGF-I, and IGFBP-3 levels.

Main Methods:

• Investigated peak GH response to ITT in 23 patients with organic GH deficiency and 35 matched controls.
• Measured mean 24-hour GH concentration (IGHC) using standard and highly sensitive GH assays.
• Assessed serum IGF-I and IGFBP-3 levels in both patient and control groups.

Main Results:

• The ITT was the only method that effectively distinguished between patients with organic GH deficiency and normal subjects.
• IGHC measurements were limited by assay sensitivity, with many undetectable values even with a more sensitive assay.
• IGF-I and IGFBP-3 levels showed significant overlap between groups, with only a minority of GH-deficient patients having low IGF-I.

Conclusions:

• The insulin-tolerance test (ITT) is the most reliable method for diagnosing organic growth hormone deficiency in adults.
• IGF-I and IGHC measurements have limitations in accurately diagnosing adult GH deficiency.
• Further research may be needed to refine diagnostic criteria, especially considering age and obesity.