Ovine CRH stimulation and 8 mg dexamethasone suppression tests in 323 patients with ACTH-dependent Cushing's syndrome.

Abstract

CONTEXT:

Determining the etiology of ACTH-dependent Cushing's syndrome (CS) is often difficult. The gold standard test, inferior petrosal sinus sampling (IPSS), is expensive and not widely available.

OBJECTIVE:

Evaluate the performance of the CRH stimulation test (CRH-ST) and the 8 mg high dose dexamethasone suppression test (HDDST) in distinguishing Cushing's disease (CD) from ectopic ACTH syndrome (EAS).

DESIGN:

Retrospective review.

SETTING:

Tertiary referral center.

PATIENTS:

323 patients with CD or EAS (n=78) confirmed by pathology or biochemical cure (n=15) in 96.

INTERVENTIONS:

CRH-ST and HDDST performed between 1986-2019.

MAIN OUTCOME MEASURES:

We calculated test sensitivity (Se), specificity (Sp), positive/negative predictive value (PPV/NPV) and diagnostic accuracy (DA) for the diagnosis of CD, and determined optimal response criteria for each test, alone and in combination.

RESULTS:

The CRH-ST performed better than the HDDST (DA 91%, 95%CI: 87% - 94% vs 75%, 95%CI: 69% - 79%). Optimal response criteria were a ≥40% increase of ACTH and/or cortisol during the CRH test and a ≥69% suppression of cortisol during the HDDST. A ≥40% cortisol increase during the CRH test was the most specific measure, PPV 99%. 74% of subjects had concordant positive CRH test and HDDST results, yielding Se 93%, Sp 98%, DA 95% and PPV 99%, with a pretest likelihood of 85%. A proposed algorithm diagnosed 64% of patients with CD with near perfect accuracy (99%), obviating the need for IPSS.

CONCLUSIONS:

CRH is a valuable tool to correctly diagnose the etiology of ACTH-dependent CS. Its current world-wide unavailability impedes optimal management of these patients.

• Authors: Henrik Elenius, Raven McGlotten, Lynnette K Nieman
• Journal: The Journal of clinical endocrinology and metabolism (J Clin Endocrinol Metab) (Aug 02 2023) ISSN: 1945-7197 [Electronic] United States
• PMID: 37531629 (Publication Type: Journal Article)
• Copyright: Published by Oxford University Press on behalf of the Endocrine Society 2023.