This is a non-interventional study enrolling approximately 1000 patients at approximately 45 sites in the (US) and will assess the prevalence of eHC in patients with rHTN.
For the purpose of this study, eHC is defined by post-dexamethasone suppression test (DST) cortisol > 1.8 μg/dL with serum dexamethasone levels ≥ 140 μg/dL in a population meeting the inclusion and exclusion criteria for this study.
rHTN is defined by the American Heart Association as 1) systolic blood pressure (SBP) above target (≥ 130 mmHg for purposes of this study) despite concurrent use of 3 or more antihypertensive medications from different classes including a diuretic at their maximally tolerated doses or 2) at target or above target SBP requiring concurrent use of 4 or more antihypertensive medications from different classes.
Each patient will have an initial visit for screening. After written informed consent and eligibility is confirmed including a urine pregnancy test (if applicable), blood pressure, weight, height and waist circumference will be checked, and medical history will be obtained. Non-fasting labs such as plasma renin activity, aldosterone, N-terminal-pro brain natriuretic peptide, complete blood count, high sensitivity C-reactive protein, hemoglobin A1c, and comprehensive metabolic panel will be collected. A urine test will also be performed for albumin to creatinine ratio.
A second visit will be at 8 AM (± 1 hour) the morning after taking 1 mg of dexamethasone at 11 PM the night before. The blood draw must be in the fasted state and will include cortisol level, lipid panel, adrenocorticotropic hormone (ACTH), and fasting glucose. Dexamethasone level will be checked automatically for any cortisol >1.8 μg/dL (eHC).
After the DST results are obtained, a third visit will be scheduled only for patients with eHC and will include a non-fasting 8 AM blood draw for ACTH and cortisol and scheduling of a non- contrast adrenal CT scan.