Diagnosis and Biochemical Confirmation of Acromegaly

Biochemical Diagnostic Criteria

• Acromegaly is definitively confirmed through biochemical testing that includes elevated insulin-like growth factor I (IGF-I) levels and failure to suppress growth hormone (GH) during an oral glucose tolerance test (OGTT) 1
• Using modern sensitive assays, GH should suppress to <1 μg/L during OGTT in normal individuals; failure to suppress confirms acromegaly 1
• The clinical significance of slightly elevated IGF-I levels remains to be established 1

Clinical Importance of Accurate Diagnosis

• Elevated GH and IGF-I levels are predictors of mortality in acromegaly 1
• Normalizing GH and IGF-I levels results in mortality rates similar to the general population 1
• Heart failure is the most common cause of death in untreated acromegaly 2

Follow-up and Treatment

• Results of GH suppression during OGTT are not useful in follow-up of medically treated patients due to inconsistent results 1