Advances in the diagnosis of acromegaly

An initial clinical suspicion of acromegaly has traditionally been the necessary first step toward making the diagnosis. However, because of the often insidious nature of the clinical syndrome, acromegaly is usually under recognized with a long delay from disease onset to diagnosis. Improvements in biochemical testing are now available that may help lead to the detection of this disease in its earlier stages, The biochemical diagnosis of acromegaly consists of documentation of an insulin like growth factor-1 level above the age and sex adjusted normal range as well as the failure of growth hormone (GH) to suppress to less than 1.0 mu g/L during an oral glucose tolerance test (OGTT). Use of highly sensitive GH assays has demonstrated, however, that a fall of GH to less than 1.0 mu g/L during an OGTT does not necessarily exclude acromegaly. Persistent frank elevation of basal GH levels is consistent with the diagnosis, but a random GH level alone is not a reliable indicator of disease status. An accurate understanding of the biochemical criteria needed for the diagnosis and to guide treatment of acromegaly is crucial. This is particularly important now because advances in therapy should enable us to tightly control the hormonal excesses in nearly all patients with acromegaly and, thus, as recent data suggest, return their increased mortality rare to that of the general population.