Objective: We examined whether the “Dexamethasone Stress Test” exhibits the requisite high predictive ability to identify individuals highly prone to develop type 2 diabetes mellitus (T2DM).

Methods: Seven years ago, we administered an oral glucose tolerance test (OGTT) to 33 individuals without T2DM and repeated the OGTT 24 hours after a single oral dose of 8 mg dexamethasone (Dex); all participants had a first-degree relative with T2DM, and close to half had prediabetes. We calculated receiver operating characteristic (ROC) curves for all parameters derived from the OGTT before and after Dex in individuals who subsequently developed diabetes compared to individuals who did not.

Results: At 7 years of follow-up, 9 individuals had developed T2DM, while 24 remained without diabetes. None of the OGTT-derived parameters before administration of Dex had an area under the ROC curve of >0.8. However, 24 hours after Dex, three parameters, including fasting plasma insulin, homeostatic model assessment-insulin resistance, and 2-hour plasma glucose level, exhibited areas under the ROC curves of 0.84, 0.86, and 0.92, respectively.

Conclusion: The Dexamethasone Stress Test appears to be a good to excellent test in identifying individuals highly prone to develop T2DM.

Abbreviations: AUC = area under the curve; Dex = dexamethasone; HOMA-IR = homeostatic model assessment-insulin resistance; NGT = normal glucose tolerance; OGTT = oral glucose tolerance test; PreDiab = prediabetes; ROC = receiver operating characteristic; T2DM = type 2 diabetes mellitus.