Wednesday, December 14, 2011

Do patients with Type 2 Diabetes Mellitus have an increased prevalence of Cushing's Syndrome?

Therese Krarup,  Thure Krarup,  Claus Hagen

Copyright © 2011 John Wiley & Sons, Ltd.

Keywords: Type 2 diabetes; Cushing's syndrome; hypercortisolism


Many clinical features are common for patients with Type 2 Diabetes Mellitus (T2DM) and Cushing's Syndrome (CS) such as central obesity, hypertension and dyslipidaemia. Patients with CS often have T2DM. Since T2DM is much more frequent than CS it is possible that some patients with T2DM have increased production of cortisol and thus represent patients with CS.

The aim of this review is to evaluate the prevalence of CS in patients with T2DM.

A search was performed in Pubmed and Medline. We found 7 prospective studies, 2 case control studies and 2 cross sectional studies.

The difficulties in diagnosing subclinical Cushing's Syndrome is discussed.

The most frequent tests for diagnosing CS, late night salivary cortisol, 1 mg dexamethasone suppression test, and urinary free cortisol are discussed and put in relation to the results of the literature found.

The observed prevalence of CS in patients with T2DM varies widely between the different studies, ranging from 0% - 9,4%. This may be due to patient selection, differences in test methodology, including choice of test, cut off values and different cortisol assays. The true prevalence of CS in T2DM has not been determined. We need more studies investigating the prevalences of CS in T2DM patients. There is a need for developing more specific tests for diagnosing CS in patients with only slightly elevated cortisol secretion and subclinical CS.

We suggest that examination for hypercortisolism should only be performed in T2DM patients with a cushingoid appearance and hypertension or truncal obesity or dyslipidaemia. Copyright © 2011 John Wiley & Sons, Ltd.

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