Frequently Asked Questions

The definition of difficult-to-control T2D varies by person, clinical practice, and experience. In the CATALYST study, people with difficult-to-control T2D were defined as having an HbA1c of ≥7.5% and ≤11.5% and taking¹:

• 3 or more T2D medications OR

• Insulin and other T2D medication(s) OR

• 2 or more T2D medications AND

  • The presence of ≥1 microvascular or macrovascular complications AND/OR

  • 2 or more hypertension medications

Moon face, dorsocervical fat pad/buffalo hump, and striae are considered highly specific Cushingoid features. However, there are many people with hypercortisolism who do not present with these phenotypic features.

These people may have multiple progressive metabolic derangements and feature comorbidities commonly seen in the general population (eg, obesity, diabetes, hypertension, and depression). The absence of Cushingoid physical features does not exclude patients from having hypercortisolism. People with an adrenal source of hypercortisolism do not typically display Cushingoid phenotypic features. In a meta-analysis published in 2019, only 0.2% (n=6/2745) of people with adrenal incidentalomas developed overt Cushingoid features.²

Many people who do not present with Cushingoid features are at risk for delayed or even missed hypercortisolism diagnosis. A retrospective study of 198 individuals with adrenal adenomas from Di Dalmazi et al revealed that people with post-DST cortisol levels >1.8 μg/dL who did not have overt Cushingoid features had a greater risk for morbidity and mortality.³

Multiple publications support the use of DST to screen for ACS. The Endocrine Society Guidelines and the European Society of Endocrinology recommend a 1-mg DST cutoff of >1.8 µg/dL to screen people who do not exhibit the clinical features or signs and symptoms but are suspected of having ACS. A 1-mg DST cutoff of >1.8 µg/dL achieves sensitivity rates greater than 95%.^4,5

The following factors may interfere with the reliability and accuracy of the results from a 1-mg DST^1,4:

• Drugs that may alter dexamethasone metabolism (eg, anticonvulsants, or other drugs that may induce CYP450 or CYP3A4 metabolism)

• Alcoholism

• Psychiatric illness

• Women on estrogen therapy including oral contraceptives

• Non-compliance with testing instructions

To help ensure accurate test results in your patients, use this 1-mg DST Patient Tool that provides directions and guidance on what to expect with screening.

No, a person with elevated post-DST cortisol levels and normal UFC results may still have an adrenal source of excess cortisol secretion. In people suspected of having an adrenal adenoma, UFC results are often normal and cannot be used to confirm a diagnosis.⁶

The Endocrine Society Guidelines recommend the use of a 1-mg DST or LNSC over a UFC test.⁴ Diagnostic tests should be used in combination with a high degree of clinical suspicion to reduce the likelihood of false positive results.

At www.cortisolincontrol.com, patients can learn about cortisol and how too much cortisol can keep blood sugar high, as well as other health issues such as high blood pressure and unexplained weight gain. Patients can learn about:

• Signs and symptoms of excess cortisol

• How to test for excess cortisol

• How to find a specialist in their area who may be able to test for excess cortisol

Cortisolincontrol.com also features an excess cortisol checklist that can help start a discussion if a DST is appropriate for the patient.