Context: Data on the overnight 1 mg-dexamethasone suppression test (ONDST) in renal dysfunction are limited. Objective: We aim to determine the normative range of ONDST cortisol across chronic kidney disease (CKD) stages and reasons for its alteration. Methods: Prospectively, 180 CKD (30 each in G2-G5/5D) patients and 30 healthy controls underwent ONDST 8 AM serum cortisol (chemiluminescent immunoassay [CLIA]).
In an exploratory cohort, 45 (15 each: G3b/G4, G5/G5D, and healthy controls) individuals’ blood biochemistry for basal (8 AM) cortisol and adrenocorticotropin (ACTH), post-ONDST 8 AM dexamethasone, ACTH, cortisol (CLIA and liquid chromatography–tandem mass spectrometry), and 4 PM cortisol was collected. Results: Post-ONDST cortisol (µg/dL) correlated inversely (r = 0.47; P < .005) with estimated glomerular filtration rate (eGFR) (mL/min/1.73 m2), with 95th percentile being 1.2 in…
