Citations

Abstract Disclosure: C.A. Villavicencio Torres: None. S. Ahmadian: None. K. Moehnke: None. V.M. Fell: None. R.L. Taylor: None. S.K. Grebe: None. A.D. Maus: None. I. Bancos: None. Background: Evaluation of adrenal disorders relies on total cortisol measurements at baseline or during dynamic testing. Accurate cortisol assessment that avoids phlebotomy may simplify the work up of adrenal disorders, decrease healthcare costs, and improve patient experience. Objectives: We aimed to compare cortisol and dexamethasone concentrations between venipuncture-based (clinical) and capillary blood samples. Methodology: We conducted a cross-sectional study (July 2024-April 2025) of adults undergoing standard-of-care cortisol measurements. Capillary blood samples were collected alongside clinical samples. Capillary measurements included total cortisol and dexamethasone (mass spectrometry). Clinical samples were tested for total cortisol (Roche immunoassay) and dexamethasone (mass spectrometry). Results: Of 318 patients (243, 77% women, median age 53 years, IQR 39-66), 227 (71%) underwent dexamethasone suppression test (DST) and 88 (28%) cosyntropin stimulation test (CST). Capillary blood collection failed in 13 (4%) patients. In patients undergoing DST, median post-dexamethasone serum cortisol was 1.3 mcg/dL (IQR 0.8-2.2), and serum dexamethasone was 0.41 mcg/dL (IQR 0.27-0.59), while median capillary cortisol was 1.5 mcg/dL (IQR 1-2.5), and capillary dexamethasone was 0.33 mcg/dL (IQR 0.21-0.51). Capillary cortisol (r=0.95, 95% CI [0.93, 0.96], p<.0001) and capillary dexamethasone (r=0.93, 95% CI [0.90, 0.95], p<.0001) showed strong correlation with their respective clinical measurements. In patients undergoing CST, median baseline serum cortisol was 7.5 mcg/dL (IQR 5-10), and median baseline capillary cortisol was 8.5 mcg/dL (IQR 6-12). Median post-CST 60-minute serum cortisol was 23 mcg/dL (IQR 20-25), while capillary cortisol was 25 mcg/dL (IQR 21-28). Baseline (r=0.77, 95% CI [0.66, 0.85], p<.0001) and post-CST 60-minute capillary cortisol (r=0.88, 95% CI [0.81-92], p<.0001) strongly correlated with clinical measurements. Post-dexamethasone cortisol in paired DST samples showed that capillary measurements were higher than serum cortisol (median difference 0.20 mcg/dL (95% CI [0.12, 0.42], p<.0001), while paired capillary dexamethasone concentrations were lower than serum dexamethasone concentrations (median difference 0.04 mcg/dL (95% CI [0.03, 0.07], p<.0001). In CST, paired baseline capillary and serum cortisol concentrations were similar (median difference 0.10 mcg/dL, 95% CI [0.3, 0.3], p=.3660), while paired post-CST 60-minute capillary cortisol was higher than serum cortisol by a median of 2.8 mcg/dL (95% CI [2, 3.2], p<.0001). Conclusion: Capillary cortisol and dexamethasone concentrations demonstrate excellent correlation with venipuncture-based measurements. Following validation with at-home collection, capillary blood measurements may serve as an alternative for evaluating adrenal disorders. Presentation: Sunday, July 13, 2025

Abstract Disclosure: K. Yu: None. J. Saini: None. E.J. Atkinson: None. S.J. Achenbach: None. V. Fell: None. I. Bancos: None. Background: Data on cognition in patients with primary aldosteronism (PA) are scarce. Mild autonomous cortisol secretion (MACS), defined based on post-dexamethasone cortisol >1.8 mcg/dL, is diagnosed in 20-30% of patients with PA. The impact of MACS on the cognition of patients with PA is unclear. Objectives: 1) to assess cognition in patients with PA versus sex-matched referent subjects with hypertension, 2) determine the differences in cognition of patients with PA (with and without MACS) and patients with MACS. Methods: A cross-sectional study, 2019-2023. Cognition was assessed by National Institute of Health Toolbox Cognition Battery and reported as T-score corrected for age, sex, race, and education. Only subjects with hypertension were included. Results: Cognitive assessment was performed in 52 patients with PA (including 11 patients with both PA and MACS, median age of 51 yrs, 30, 58% women), 47 patients with MACS (median age of 57 yrs, 31, 66% women), and 52 referent subjects (median age of 66 yrs, 30, 58% women). When compared to referents, and after age adjustment, patients with PA had lower cognition: fluid composite cognition β of -6.3 (P=0.014) and total composite of -5.6 (P=0.016). When compared to patients with MACS, and after age and sex adjustment, patients with PA had a similar total composite cognition score (β=3.6, P=0.108) but a higher fluid composite score (β=4.7, P=0.044). No differences in cognition were found between patients with PA with and without MACS, possibly due to low sample size. Conclusion: Patients with PA demonstrate lower cognition when compared to referents with hypertension. Patients with PA had a higher fluid cognition compared to patients with MACS. Future studies should delineate the impact of hyperaldosteronism vs MACS on cognition of patients with PA. Presentation: Monday, July 14, 2025

Abstract Disclosure: S.R. Chacko: None. J. Saini: None. S. Sharma Sharma: None. S. Ahmadian: None. S.J. Achenbach: None. E. Atkinson: None. V. Fell: None. J.J. Van Gompel: None. W.F. Young, Jr.: None. I. Bancos: None. Context: Evidence on the duration of postoperative adrenal insufficiency (AI) in patients with endogenous hypercortisolism is scarce. Objective: To determine the duration of postoperative AI and to identify factors associated with the duration of AI in patients undergoing surgery for endogenous hypercortisolism.Methods: We conducted a single center prospective cohort study, 2019-2024, of patients with endogenous hypercortisolism [Cushing syndrome (CS) or mild autonomous cortisol secretion (MACS)] treated with surgery. Associations of demographics, BMI, clinical and biochemical hypercortisolism severity, subtype of hypercortisolism, presurgical hypercortisolism duration and glucocorticoid type in relation to duration of AI were investigated. Results: The 110 patients [36% MACS, 46% pituitary CS, 15% adrenal CS, 3% ectopic CS, median age 50 years (IQR: 40-60), 82% women] who developed postsurgical AI were followed for a median duration of 26 months (IQR: 15-38). By the end of follow up, 96 patients (87%) had recovery of AI. The median time to recovery of AI was shorter in MACS vs. Overt Cushing syndrome (3.0 months (95% CI: 2.5-6.2) vs. 12.3 months (95% CI 9.0-17.3), P =0.002). Biochemical severity score (r=0.32, P=0.002) and duration of preoperative hypercortisolism symptoms (r=0.29, P=0.005), but not age, sex, BMI, clinical severity, or glucocorticoid type were associated with the duration of AI. We found no differences in the duration of AI between patients with ACTH-dependent vs ACTH-independent CS (12.3 months (95% CI: 6.0-17.2) vs 13.9 months (95% CI: 9.0-25.5), P =0.7).Conclusion: In this interim analysis, we showed that after surgical remission of endogenous hypercortisolism, duration of postoperative AI was longer in CS compared to MACS. Additionally, higher biochemical hypercortisolism severity score and a longer duration of symptoms suggestive of hypercortisolism were associated with a longer duration of postoperative AI. Presentation: Sunday, July 13, 2025

Abstract Disclosure: I. Bancos: AstraZeneca. A. Ben-Shlomo: AstraZeneca. O. Hamidi: Recordati Rare Diseases, Neurocrine Biosciences, Corcept Therapeutics, Crinetics, Camurus, Xeris. A. Hamrahian: AstraZeneca. W. Huang: None. L.S. Kirschner: Corcept Therapeutics, AstraZeneca, Crinetics, Sparrow Pharma, Spruce Biosciences. R. Sam: AstraZeneca. A.F. Turcu: AstraZeneca. A. Lihn: AstraZeneca. A. Mallappa: AstraZeneca. S. Perl: AstraZeneca. B. Tuyishimire: AstraZeneca. M.J. Brown: GlaxoSmithKline, Pfizer, Inc., Bristol-Myers Squibb, AstraZeneca. Introduction: Mineralocorticoid receptor antagonist (MRA) treatment for primary aldosteronism (PA) has limited efficacy in some patients. Highly selective, competitive aldosterone synthase inhibitors (ASIs) offer an alternative therapeutic approach. SPARK (NCT04605549) was a Phase 2, open-label, multicenter trial of the ASI baxdrostat in patients with PA. Methods: Eligibility entailed: aged ≥18 years; diagnosis of PA; willingness to discontinue MRA up to 4 weeks before baxdrostat initiation; and systolic blood pressure (SBP) rise ≥20 mmHg or SBP ≥160 mmHg after discontinuation of MRA, or SBP ≥150 mmHg for patients with newly diagnosed PA who had not taken MRAs in the past 12 weeks. Patients entered a 12-week treatment period (Part 1) of once daily baxdrostat 2 mg, up-titrated to 4 mg or 8 mg at week (W) 4 or W8, respectively, if there was no significant risk of hypotension. Baxdrostat could be down-titrated to 2 mg or continued at 4 mg as needed. After W12, patients could continue baxdrostat up to W72 (Part 2) with doses at investigators’ discretion. Primary endpoints were safety, tolerability and change from baseline in mean seated SBP at W12. Results: Fifteen patients enrolled and completed Part 1; 14 patients continued to Part 2. Median (range) age was 54 (32, 75) years, 67% of patients were male, 47% were White, and median (range) body mass index was 32.0 (24.4, 41.4) kg/m2. At baseline, plasma renin activity (PRA) was <1 ng/mL/h in 12/15 (80%) patients, and 8/15 (53%) patients had hypokalemia (serum potassium <3.5 mmol/L). Mean (range) baseline SBP was 151.5 (130, 174) mmHg; diastolic BP (DBP) was 90.3 (74, 103) mmHg. At W12, mean (range) SBP change from baseline was –29.5 (–47, –12), –24.4 (–31, –17), and –23.9 (–47, –8) mmHg for patients on baxdrostat 2 mg (n=2), 4 mg (n=5), and 8 mg (n=7), respectively; DBP change was –8.0 (–14, –2), –10.4 (–20, 0), and –11.6 (–25, 7) mmHg, respectively. Overall, 11/15 (73%) patients achieved BP <140/90 mmHg and 6/15 (40%) achieved BP <130/80 mmHg at W12; reduced BP persisted in Part 2. No deaths were reported. Nine out of 15 (60%) patients had a treatment-emergent adverse event (TEAE) during W4–W12 of Part 1 (all mild/moderate), including 1/15 (7%) patient with hyperkalemia; no serious TEAEs were reported. In Part 2, 14/14 (100%) patients had a TEAE (most mild/moderate), including 5/14 (36%) patients with hyperkalemia; one serious TEAE of hyperkalemia was reported. Mean (standard deviation, SD) serum potassium levels increased from 3.9 (0.6) mEq/L at baseline to 4.7 (0.5) mEq/L at W12. Mean (SD) 24-h urine aldosterone excretion at baseline and W12 were 30.3 (17.5) and 3.2 (2.7) µg/day, respectively. At W12, 7/15 (47%) patients had achieved unsuppressed PRA (≥1.0 ng/mL/h). Conclusions: Baxdrostat, an ASI, was well tolerated and led to reduced BP and unsuppressed renin in patients with PA. Inhibiting aldosterone synthase may be an alternative to MRAs for treating PA. Presentation: Sunday, July 13, 2025

Abstract Disclosure: R.J. Auchus: Has been involved in contracted research with companies such as Neurocrine Biosciences/Neurocrine UK, LTD, Spruce Biosciences, Corcept Therapeutics, Crinetics Pharmaceuticals, Recordati Rare Diseases, Adrenas Therapeutics, and Mineralys Pharmaceuticals, Served as consultant for organizations like Quest Diagnostics, Corcept Therapeutics, Xeris Pharmaceuticals, Crinetics Pharmaceuticals, Novo Nordisk, Neurocrine Biosciences/Neurocrine UK, LTD, Recordati Rare Diseases, H Lundbeck A/S, Sparrow Pharmaceuticals, Astellas Pharmaceuticals, and Acerand Therapeutics. O. Hamidi: Advisory board member for Neurocrine Biosciences, Corcept Therapeutics, Recordati Rare Diseases, Crinetics Pharmaceuticals, Inc, Camurus, Xeris Pharmaceuticals, Inc, Educational speaking engagement with Recordati Rare Diseases. I. Bancos: None. K. Saag: Recieved grants or contracts from Amgen, Arthrosi, Horizon, LG Pharma, Radius, and Olatec, Received consulting fees from Amgen, Anthrosi, Atom Bioscience, Horizon, LG Pharma, Angitia, and Gruenthal. H. Falhammar: None. U. Srirangalingam: Consulting fees from Crinetics Pharmaceuticals, Diurnal Ltd and H Lundbeck A/S. M. Calanchini: None. E. Jen: Full-time employee of Neurocrine Biosciences, Inc. V.H. Lin: Full-time employee of Neurocrine Biosciences, Inc. J. Sturgeon: Full-time employee of Neurocrine Biosciences, Inc. J.L. Chan: Full-time employee of Neurocrine Biosciences, Inc. Background: Crinecerfont, a corticotropin releasing factor type 1 receptor (CRF1) antagonist, is a first-in-class medication that is FDA-approved for adjunctive treatment to glucocorticoid (GC) replacement to control androgens in patients with classic congenital adrenal hyperplasia (CAH). In the Phase 3 CAHtalyst™ Adult study (NCT04490915), crinecerfont (100 mg BID) significantly reduced adrenal androgens, enabling substantial GC dose reductions from Day 1 baseline (BL) at the end of double-blind placebo-controlled (DBPC) treatment at Week 24, with a least-squares (LS) mean percent change of -27.3% vs. -10.3% for placebo (LS mean difference [LSMD] -17.0%, P<0.0001). At the end of open-label (OL) treatment at Month 12, mean percent decreases from BL in GC dose were -24.6% in participants who continued on crinecerfont (CFT/CFT) and -29.7% in those who switched from placebo (PBO/CFT). Objective: To evaluate clinical outcomes in adults with CAH who received up to 1 year of crinecerfont, in the context of substantial GC dose reductions. Methods: Outcomes related to excess adrenocorticotropic hormone (ACTH)/androgens (e.g., hirsutism in female participants) and GC exposure (e.g., body mass index [BMI], insulin resistance, hyperlipidemia) were analyzed at the end of DBPC treatment (Week 24) and the end of OL treatment (Month 12). DBPC outcomes with P-values are presented as LS mean changes with LSMD. Results: In female participants, mean hirsutism visual analog scale scores (out of 0 [no symptoms] to 100 [very severe symptoms]) were 40.6 (crinecerfont) and 37.4 (placebo) at BL. Changes from BL at end of DBPC (Week 24) and OL (Month 12) were: Week 24 (-9.8 for crinecerfont [n=58] vs -2.8 placebo [n=27], LSMD -7.0, P=0.1564); Month 12 (-11.5 CFT/CFT [n=56], -12.9 PBO/CFT [n=27]). Mean BMI at BL was 30.1 kg/m2 (crinecerfont) and 29.0 kg/m2 (placebo). Changes from BL were: at Week 24 (-0.4 vs. -0.02 for crinecerfont [n=118] vs. placebo [n=57], LSMD -0.40, P=0.1068); at Month 12 (-0.8 CFT/CFT [n=114], -0.4 PBO/CFT [n=56]). Mean homeostatic model assessment of insulin resistance values were high at BL (crinecerfont 3.2, placebo 3.0). Changes from BL were: at Week 24 (-0.6 vs. -0.4 for crinecerfont [n=61] vs placebo [n=29], LSMD -0.29, P=0.3454); at Month 12 (-0.5 CFT/CFT [n=107], -0.9 PBO/CFT [n=54]). Mean values for cholesterol (total, LDL, and HDL) and triglycerides were within normal range or near optimal at BL and remained stable. Conclusion: Adults with CAH who received up to 1 year of crinecerfont continued to show improvements in BMI and insulin resistance, as expected with lower GC doses. Moreover, despite substantial GC dose reductions, hirsutism in female participants improved with crinecerfont. Given the known adverse effects of ACTH/androgen excess and chronic supraphysiologic GC exposure, these results represent a promising therapeutic advancement in CAH. Presentation: Sunday, July 13, 2025

Abstract Disclosure: M. Fleseriu: None. C.P. Badiu: None. I. Bancos: None. E.B. Geer: None. M. Orbetzova: None. J.M. Silverstein: None. I. Uzunova: None. K.C. Yuen: None. T.K. Marmon: None. D.A. Katz: None. F.S. Czerwiec: None. Introduction: 11β-hydroxysteroid dehydrogenase type 1 (HSD-1) regulates exposures of intracellular receptors to active glucocorticoids. HSD-1 deficiency suppresses a Cushing syndrome (CS) phenotype despite presence of hypercortisolism.1-3 Treatment with clofutriben (C), a potent and specific inhibitor of HSD-1, might improve CS comorbidities by decreasing intracellular cortisol. Methods: Seventeen adults with CS (16 pituitary, 1 ectopic), and type 2 diabetes (T2D), impaired glucose tolerance (IGT), hypertension (HTN), hyperlipidemia, or osteopenia were randomized to a total of 12 weeks of oral C 6mg/d and 12 weeks of matching placebo (P) in 2 blinded sequences (PCCP, CCPP; “P” or “C” representing 6-week periods). Patients were offered open-label C treatment on completion. Primary endpoint was urinary ratio of cortisol and cortisone metabolites at Week 6 (hepatocellular HSD-1 activity biomarker). Key exploratory endpoints (and applicable population) at Week 6 were OGTT-AUCglucose decrease 25% (IGT/T2D), HbA1c decrease ≥ 0.5% (T2D), systolic blood pressure decrease ≥ 5mmHg or decreased treatment (HTN), and normalization of urinary free cortisol (baseline >1.5xULN). Results: Mean baseline HSD-1 ratio was 1.95 +/- 0.171. At Week 6, mean ratio was 0.21 +/- 0.091 with C and 2.01 +/- 0.263 with P. More patients responded at Week 6 to C on OGTT-AUCglucose (4/8 v 0/5), HbA1c (4/5 v 0/4), systolic blood pressure (5/7 v 2/4), and urinary free cortisol (3/8 v 0/6). Concomitant medications for T2D were reduced in 4 C-treated but increased in 2 P-treated patients. For HTN there were also 4 reductions for C-treated and 1 increase for P-treated patients. One patient succumbed to ectopic Cushing’s due to cervical carcinoma after discontinuing the trial. Four patients discontinued for reasons other than an adverse event (AE). One serious AE of vomiting (possible glucocorticoid withdrawal syndrome per investigator) led to temporary drug interruption. Common AEs (≥ 3 patients) included Arthralgia, Fatigue, Headache, and Nausea, but only Headache was more common in C during the P-controlled period. There was no evidence of clinical or biochemical (defined by low morning plasma cortisol) adrenal insufficiency. All 13 patients who completed elected to enter the open-label extension (current treatment duration 3-15 months). Conclusions: Clofutriben decreased hepatic HSD-1 activity adequately to confer clinical benefit while maintaining safety and overall tolerability. These limited data support clofutriben’s potential for clinical improvement without adrenal insufficiency. References: 1Tomlinson JW 2002; 2Arai H 2008; 3Weber RJ 2024 Presentation: Sunday, July 13, 2025

Abstract Disclosure: J. Saini: None. E. Ferreira Taveras: None. Y. Hleibiehova: None. B. Bahrani Fard: None. M. Suresh: None. R. Sandooja: None. B. Salama: None. V. Fell: None. S. Achenbach: None. E.J. Atkinson: None. I. Bancos: None. Context: Patients with endogenous hypercortisolism experience glucocorticoid withdrawal syndrome (GWS) post-surgery. Meditation may be an effective intervention to alleviate the severity of GWS. Objective: To determine the acceptability of portable, wearable EEG device for guided meditation (MUSE headband) and the impact of MUSE use on GWS and quality of life 12 weeks post-surgery. Methods: We conducted a single-center prospective cohort study of adults with endogenous hypercortisolism undergoing curative surgery, 2019-2024. Patients had baseline and post-surgical assessments over 12 weeks. The study comprised of patients using MUSE for ≥ 6 weeks (MUSE cohort) and patients matched by age, sex, BMI, hypercortisolism type, and glucocorticoid type at 1:4 ratio. Quality of life and symptoms of GWS were assessed with AddiQoL, Cushing Quality of Life, and Short Form-36 mental and physical component (SF-36 MCS and PCS) questionnaires. Results: MUSE was offered to 52 patients, and 22 (42%) used MUSE for ≥ 6 weeks within 12 weeks post-surgery. At baseline, when compared to 88 matched subjects, 22 MUSE participants demonstrated a similar prevalence of comorbidities, clinical and biochemical hypercortisolism severity, but lower AddiQoL (mean 73 vs 66, P=0.031) and SF-36 MCS (mean 39 vs 33, P=0.022). At 12 weeks, these differences in quality of life were no longer present. After adjusting for age, sex, BMI, clinical severity score, and baseline quality of life, MUSE use was an independent predictor of improved SF- 36 PCS at 12 weeks post-surgery (beta 4.2, 95% CI: 0.5-7.9, P=0.026). Conclusions: Meditation intervention post-surgery may improve symptoms of GWS and accelerate recovery. Presentation: Sunday, July 13, 2025

Abstract Disclosure: S.R. Chacko: None. C.A. Villavicencio Torres: None. K. Yu: None. S.G. Waguespack: None. L. Lu: None. Z. Belaya: None. T. Bandgar: None. A. Sada: None. O. Ragnarsson: None. B. Altieri: None. A. Newman: None. P. Vibhatavata: None. M. Tóth: None. E.V. Varlamov: None. C. Badiu: None. A. Paissan: None. M. St-Jean: None. H. Falhammar: None. N. Imamudeen: None. L. Haberbosch: None. M. Bobrowicz: None. A. Tabarin: None. R. Shah: None. M.R. Gadelha: None. A. Peersen: None. W.F. Young: None. J. Kaplan: None. J. Varghese: None. M.A. Habra: None. O. Golounina: None. G.A. Melnichenko: None. A.R. Lila: None. C. Yamichannaiah: None. I. Bancos: None. Context: Cushing syndrome (CS) due to ectopic ACTH secretion (EAS) is a rare condition, associated with severe hypercortisolism and consequent morbidity and mortality. Its varied and often emergent presentation make diagnosis and treatment challenging. Objectives: 1.Characterize clinical and biochemical presentation of EAS. 2.Describe the scope of hypercortisolism-related complications, overall and CS-specific mortality. 3.Identify factors associated with CS-specific mortality. Methods: We conducted a multicenter retrospective cohort study in patients with EAS at 37 centers. Outcomes were clinical/biochemical severity scores, complications, overall and CS-specific mortality. Results: In 1053 patients [median age at diagnosis 52 years (IQR 37-64), 57% women], metastatic disease was present at diagnosis in 585 (56%). The most common sources of EAS were bronchial neuroendocrine neoplasm (NEN) (304, 29%), pancreatic NEN (114, 11%) and small cell lung carcinoma (114, 11%), with the source of EAS being occult in 192 (18%). Clinical and biochemical severity scores were severe in 475 (45%) and 873 patients (92%) respectively. Hypokalemia was present in 819 patients (78%) in the year prior to diagnosis. Of 342 patients (32%) who had IPSS, 301 (88%) suggested an ectopic source, 7 (2%) a pituitary source, and 23 (7%) were non-diagnostic. Of 595 patients who had both functional and cross-sectional imaging, discordant findings were seen in 122 (21%), concordant lesion was seen on both in 326 (55%), and no lesion in 147 (25%). Of those with discordant results, cross-sectional imaging was accurate in 66 (54%) and functional imaging in 56 (46%).Management included medical therapy alone in 237 (23%), surgical excision of the source of EAS in 158 (15%), bilateral adrenalectomy in 77 (7%) and multimodal therapies in 498 patients (47%). Complications within 5 years after diagnosis included hospitalization related to CS or its therapy in 351 (33%), infection in 337 (32%), thromboembolic event in 102 (10%), cardiovascular event in 83 (8%) and cerebrovascular event in 27 (3%). During a median follow-up of 35 months (IQR 20-122) from CS diagnosis, death occurred in 462 patients (44%), with the cause of death related to CS in 149 (14%). CS-specific mortality was higher in metastatic compared with non-metastatic disease (19% vs. 7%, P<0.001). On multivariable analysis of age, sex, clinical and biochemical severity, older age (HR 1.03, 95% CI: 1.02-1.04) and lower clinical severity score (HR 0.97, 95% CI: 0.94-0.99), were associated with higher CS-specific mortality. Conclusion: Our interim analysis, the largest worldwide, found that most patients with EAS had severe hypercortisolism and hypokalemia. Metastatic disease was present in 56%, and the source of EAS was occult in 18%. CS-related death occurred in 14%, emphasizing the need for urgent management. Presentation: Monday, July 14, 2025

Abstract Disclosure: C.A. Villavicencio Torres: None. S. Ahmadian: None. V.M. Fell: None. K. Moehnke: None. Y. Chai: None. R.L. Taylor: None. S.K. Grebe: None. A.D. Maus: None. I. Bancos: None. Background: Current standard-of-care assessment of adrenal disorders relies on the venipuncture-based total cortisol measurements. Salivary cortisol (SalF) and cortisone (SalE) measurements have advantages such as a more accurate assessment of patients with cortisol-binging globulin abnormalities and the convenience of at-home non-invasive testing. Aims: This study aimed to compare concentrations of cortisol and dexamethasone between clinical (venipuncture-based) and saliva samples. Methodology: We conducted a cross-sectional study (July 2024-January 2025) of adults undergoing overnight dexamethasone suppression test (DST) or cosyntropin stimulation test (CST). Saliva samples were collected alongside clinical samples. Saliva measurements included cortisol, cortisone, and dexamethasone (mass spectrometry), while clinical samples were tested for total cortisol (Roche immunoassay) and, in a subgroup, dexamethasone (mass spectrometry). Results: Of 241 patients (186 (77%) women, median age 53 years (IQR 39-66)), 178 (74%) provided samples as a part of DST and 63 (26%) as a part CST. An inability to provide sufficient saliva for analysis was found in 5 patients (2%). In patients undergoing DST, median post-dexamethasone serum total cortisol was 1.3 mcg/dL (IQR 0.8-2.2), and median serum dexamethasone (SerD) was 0.43 mcg/dL (IQR 0.3-0.6) based on clinical samples, while median SalF was 10.2 ng/dL (IQR 6.6-23.6), SalE was 78.6 ng/dL (IQR 52.8-131.1), and saliva dexamethasone (SalD) was 60 ng/dL (IQR 41-93). SalE (r=0.92, p<.0001) demonstrated a stronger correlation than SalF (r=0.85, p<.0001) when compared with post-dexamethasone serum total cortisol measurements. SalD (r=0.85, p<.0001) correlated with SerD measurements. In patients undergoing CST, median baseline serum total cortisol was 7.2 mcg/dL (IQR 4.6-10) based on clinical samples, while median baseline SalF was 86.6 ng/dL (IQR 38.3-166.3), and median SalE was 707 ng/dL (IQR 347-906). Median peak 60-minute serum total cortisol was 21.5 mcg/dL (IQR 18-24), while SalF was 870.4 ng/dL (IQR 440-2904) and SalE was 2501 ng/dL (IQR 1770-3193). Both baseline (r=0.92, p<.0001) and 60 min peak post-cosyntropin SalE (r=0.84, p<.0001) demonstrated a strong correlation with venipuncture-based measurements. SalF had a weaker than SalE correlation at both baseline (r=0.88, p<.0001) and 60 min peak post-cosyntropin (r=0.79, p<.0001). Conclusion: Our study demonstrates that salivary measurements of cortisone, cortisol and dexamethasone strongly correlate with standard-of-care venipuncture concentrations following DST and CST. SalE showed the stronger than SalF correlation with venipuncture-based serum total cortisol concentrations. Presentation: Sunday, July 13, 2025

Abstract Disclosure: S. Ahmadian: None. S.R. Chacko: None. S. Sharma Sharma: None. V.M. Fell: None. A. Peersen: None. E.J. Atkinson: None. K.L. Moehnke: None. Y. Chai: None. S.K. Grebe: None. A.D. Maus: None. I. Bancos: None. Background: Cortisol secretion follows a circadian pattern with highest concentrations in the morning, and lowest at night. Loss of circadian cortisol variation has been reported in patients with Cushing syndrome (CS), however, is scarcely investigated in patients with mild autonomous cortisol secretion (MACS). Outpatient assessment of late night and early morning salivary cortisol and cortisone may serve as a valuable diagnostic tool in patients with hypercortisolism. Methods: We conducted a single-center cross-sectional study of adults evaluated at our center between 04/2024 and 04/2025. The study included patients with Cushing’s syndrome (CS), mild autonomous cortisol secretion (MACS), and referent subjects without known adrenal disorders. Participants were provided with two cotton swabs (Salivettes) and instructed to collect saliva samples at two standardized time points: at bedtime (PM) and on waking (AM). Each swab was kept in the mouth for 2-2.5 minutes. Saliva was analyzed for cortisol and cortisone using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Delta cortisol and delta cortisone were defined as the difference between AM and PM concentrations for each individual and were calculated for all participants. Results: A total of 82 patients (32 with ACTH-dependent CS, 5 with ACTH-independent CS, and 45 with MACS), median age of 55 years [IQR 44-65], 63 (77%) women, and 71 referent subjects, median age of 34 years [IQR 28-42], 54 (76%) women, were included. Delta cortisol was higher in referents (median of 212 ng/dL, [IQR 157-358]) vs patients with CS (median 95 ng/dL [IQR -21-184]) or MACS (median 131 ng/dL, [IQR 91-229]). Similarly, delta cortisone was also highest in referents with a median of 828 ng/dL [IQR 612-1131] versus median of 211 ng/dL [IQR -58-468] in CS and 484 ng/dL [IQR 189-849] in MACS. When compared to referents in an age- and sex-adjusted linear regression model, delta cortisone was lower in both patients with CS (est -1.3 (95%CI -1.75 to -0.85), P<0.001 and MACS (est -0.66, 95%CI of -1.17 to -0.16, P=0.010). Delta cortisol was lower in patients with CS (est -1.32, 95%CI -2.11 to -0.54, P=0.001), but not MACS (est -0.51, 95%CI -1.39 to 0.36). Conclusion: Patients with both CS and MACS demonstrate a blunted circadian salivary cortisol and cortisone secretion, as reflected by a lower delta cortisol and cortisone when compared to referent subjects. Assessment with delta salivary cortisone in patients with MACS may be more valuable than a standard of care late night salivary cortisol assessment. Presentation: Sunday, July 13, 2025