In the overnight dexamethasone suppression test, 1.0 mg loading is superior to 0.5 mg loading for diagnosing subclinical adrenal Cushing's syndrome based on plasma dexamethasone levels determined using liquid chromatography-tandem mass spectrometry

Assessment of plasma dexamethasone levels after 1-mg dexamethasone suppression test in adults with obesity

BACKGROUND

The 1-mg overnight dexamethasone suppression test is the most frequently used screening test for Cushing's syndrome. It has been proposed that people with obesity may have insufficient plasma dexamethasone levels for the test which may result in false positives. We sought to compare the plasma dexamethasone levels after 1-mg dexamethasone suppression test in healthy obese participants and in optimal-weight participants.

METHODS

A total of 30 optimal-weight participants (BMI ≤ 25 kg/m2 ) and 62 obese participants (BMI > 25 kg/m2 ) were enroled in the study. Obese participants were further divided into class 1 (25-29.9 kg/m2 ) and class 2 (>30 kg/m2 ). After a standard overnight 1-mg dexamethasone suppression test, blood samples were obtained for serum cortisol and plasma dexamethasone levels. Plasma dexamethasone levels were quantified using liquid chromatography - mass spectrometry (LC-MS/MS).

RESULTS

No significant difference in plasma dexamethasone levels were found between obese and optimal-weight participants (3.31 ± 1.35 vs. 2.82 ± 1.11 nmol/L, mean ± SD; p = .09 respectively). There were also no correlations found between sex, BMI, body surface area and plasma dexamethasone levels. There was also no significant difference in the proportion of participants who achieved a plasma dexamethasone level >3.3 nmol/L in comparison between obesity class 1, obesity class 2, and optimal-weight groups.

CONCLUSION

Our results suggest that obesity does not affect plasma dexamethasone levels. However, dexamethasone measurement may still be helpful in patients who are being investigated for Cushing's syndrome and suspected to have a false-positive DST.

Management of Adrenal Cortical Adenomas: Assessment of Bone Status in Patients with (Non-Functioning) Adrenal Incidentalomas

Our aim is to analyse the bone profile in adults with (non-functioning) adrenal incidentalomas (AIs), specifically addressing the impact of autonomous cortisol secretion (ACS). This narrative review, based on a PubMed search from inception to February 2023 (case reports, non-ACS, and other secondary causes of osteoporosis were excluded), included 40 original studies, a total of 3046 patients with female prevalence (female:male ratio of 1921:1125), aged between 20.5 and 95.5 years old. This three decade-based analysis showed that 37 studies provided dual-energy X-ray absorptiometry (DXA) information; another five studies reports results on bone micro-architecture, including trabecular bone score (TBS), spinal deformity index, and high-resolution peripheral quantitative computed tomography; 20 cohorts included data on bone turnover markers (BTMs), while four longitudinal studies followed subjects between 1 and 10.5 years old (surgical versus non-adrenalectomy arms). Post-dexamethasone suppression test (DST) cortisol was inversely associated with bone mineral density (BMD). TBS predicted incidental vertebral fractures (VFx) regardless of BMD, being associated with post-DST cortisol independently of age and BMD. Low BTMs were identified in ACS, but not all studies agreed. An increased prevalence of ACS-related osteoporosis was confirmed in most studies (highest prevalence of 87.5%), as well as of VFx, including in pre-menopause (42.5%), post-menopause (78.6%), and male patients (72.7%) depending on the study, with a 10-fold increased incidental VFx risk up to a 12-fold increased risk after a 2-year follow-up. No specific medication against osteoporosis is indicated in ACS, but adrenalectomy (according to four studies) should be part of the long-term strategy. This bone profile case sample-based study (to our knowledge, one of the largest of its kind) showed that AIs, including the subgroup designated as having ACS, embraces a large panel of osseous complications. The level of evidence remains far from generous; there are still no homogenous results defining ACS and identifying skeletal involvement, which might be a consequence of different investigation clusters underling adrenal and bone assessments over time. However, bone status evaluations and associated therapy decisions remain an essential element of the management of adults with AIs-ACS.

Primary aldosteronism with mild autonomous cortisol secretion increases renal complication risk

OBJECTIVE

In primary aldosteronism (PA), renal impairment has been identified as an important comorbidity. Excess cortisol production also may lead to renal damage; thus, concomitant mild autonomous cortisol secretion (MACS) may predispose PA patients to renal disorders. However, there is limited evidence to support this claim. Therefore, this study aimed to determine whether the concurrence of MACS and PA increases the risk of renal complications.

DESIGN

This study is a retrospective cross-sectional study.

METHODS

A total of 1310 patients with PA were stratified into two groups according to 1 mg dexamethasone suppression test (DST) results (cut-off post-DST serum cortisol 1.8 µg/dL): MACS (n = 340) and non-MACS (n = 970). The prevalence of renal complications was compared between the group. We also performed multiple logistic regression analysis to determine factors that increase the risk for renal complications.

RESULTS

The prevalence of lowered estimated glomerular filtration rate (eGFR) and proteinuria was nearly twice higher in the MACS group than in the non-MACS group. Not only plasma aldosterone concentration (PAC) but also the presence of MACS was selected as independent factors that were associated with the two renal outcomes. The risk of lower eGFR or proteinuria in patients who had MACS and higher levels PAC was several folds higher than in those who had an absence of MACS and lower levels of PAC.

CONCLUSIONS

MACS is an independent risk factor for renal complications in patients with PA, and MACS concomitant with higher aldosterone secretion in PA patients causes an increase in the risk of developing renal complications.

Dexamethasone measurement during low-dose suppression test for suspected hypercortisolism: threshold development with and validation

BACKGROUND AND AIM

Dexamethasone Suppression Test (DST), recommended for Cushing's Syndrome (CS) diagnosis, explores the pituitary feedback to glucocorticoids. Its diagnostic accuracy could be affected by dexamethasone bioavailability, and therefore, we have developed and validated a dexamethasone threshold after 1-mg DST.

MATERIALS AND METHODS

We studied 200 subjects: 125 patients were considered retrospectively and 75 were enrolled prospectively as the validation cohort. Serum dexamethasone, Late Night Salivary Cortisol (LNSC), and Urinary Free Cortisol (UFC) were measured with LC-MS/MS. Normal LNSC and UFC levels were used to exclude CS. The lower 2.5th percentile of dexamethasone distribution in non-CS patients with cortisol ≤ 50 nmol/L after 1-mg DST was used as threshold.

RESULTS

16 patients were CS and 184 non-CS (108 adrenal incidentaloma and 76 excluded CS); 4.5 nmol/L resulted the calculated threshold. Cortisol after 1-mg DST confirmed high sensitivity (100% at 50 nmol/L cut-off) and moderate-low specificity (63%, increased to 91% at 138 nmol/L) to diagnose CS in the whole cohort of patients. We could reduce the number of false-positive results (from 10 to 6 and from 7 to 4 in AI and excluded CS) considering adequate dexamethasone levels. Dexamethasone levels were not affected by hypercortisolism, age, gender, smoke, weight, and creatinine. 6% of non-CS patients did not achieve adequate dexamethasone levels (40% of tests with serum cortisol > 138 nmol/L after 1-mg DST).

CONCLUSIONS

We developed and validated the routine dexamethasone measurement during 1-mg DST: it is independent from patient's clinical presentation, and it should be used to increase the specificity of serum cortisol levels.

Prospective Evaluation of Late-Night Salivary Cortisol and Cortisone by EIA and LC-MS/MS in Suspected Cushing Syndrome

Context

Late-night salivary cortisol (LNSC) measured by enzyme immunoassay (EIA-F) is a first-line screening test for Cushing syndrome (CS) with a reported sensitivity and specificity of >90%. However, liquid chromatography-tandem mass spectrometry, validated to measure salivary cortisol (LCMS-F) and cortisone (LCMS-E), has been proposed to be superior diagnostically.

Objective, Setting, and Main Outcome Measures

Prospectively evaluate the diagnostic performance of EIA-F, LCMS-F, and LCMS-E in 1453 consecutive late-night saliva samples from 705 patients with suspected CS.

Design

Patients grouped by the presence or absence of at least one elevated salivary steroid result and then subdivided by diagnosis.

Results

We identified 283 patients with at least one elevated salivary result; 45 had an established diagnosis of neoplastic hypercortisolism (CS) for which EIA-F had a very high sensitivity (97.5%). LCMS-F and LCMS-E had lower sensitivity but higher specificity than EIA-F. EIA-F had poor sensitivity (31.3%) for adrenocorticotropic hormone (ACTH)-independent CS (5 patients with at least 1 and 11 without any elevated salivary result). In patients with Cushing disease (CD), most nonelevated LCMS-F results were in patients with persistent/recurrent CD; their EIA-F levels were lower than in patients with newly diagnosed CD.

Conclusions

Since the majority of patients with ≥1 elevated late-night salivary cortisol or cortisone result did not have CS, a single elevated level has poor specificity and positive predictive value. LNSC measured by EIA is a sensitive test for ACTH-dependent Cushing syndrome but not for ACTH-independent CS. We suggest that neither LCMS-F nor LCMS-E improves the sensitivity of late-night EIA-F for CS.

Adrenal Hypercortisolism: A Closer Look at Screening, Diagnosis, and Important Considerations of Different Testing Modalities

Although prolonged hypercortisolism is associated with increased mortality and substantial morbidity, the clinical signs and symptoms are wide ranging and often nonspecific, contributing to challenges in diagnosis, as well as treatment delays. Greater awareness is needed among clinicians to help identify which patients should undergo biochemical screening for excess cortisol. Several biochemical tests are available, each with important caveats that should be considered in the context of the individual patient. Cortisol secretion varies widely, further complicating the biochemical diagnosis of hypercortisolism, which relies on the use of definitive cutoff values. Patients with hypercortisolism resulting from adrenal adenomas, including those discovered incidentally, often do not present with overt Cushingoid features (plethora, striae, muscle weakness, moon facies, etc.). However, the consequences of prolonged exposure to even slight elevations in cortisol levels are profound, including increased risk of diabetes, hypertension, fractures, cardiovascular events, and mortality. Because most cases of hypercortisolism resulting from an adrenal adenoma can be managed, it is imperative to identify patients at risk and initiate testing early for the best outcomes. The aim of this report is to increase awareness of the indications for screening for hypercortisolism and to review the biochemical screening tests and diagnosis for hypercortisolism associated with adrenal adenomas.

New diagnostic criteria of adrenal subclinical Cushing's syndrome: opinion from the Japan Endocrine Society

New diagnostic criteria and the treatment policy for adrenal subclinical Cushing's syndrome (SCS) are proposed on behalf of the Japan Endocrine Society. The Japanese version has been published, and the essential contents are presented in this English-language version. The current diagnostic criteria for SCS have elicited two main problems: (i) the relatively low reliability of a low range of serum cortisol essential for the diagnosis by an overnight 1-mg dexamethasone suppression test (DST); (ii) different cutoff values for serum cortisol after a 1-mg DST compared with those of other countries. Thus, new criteria are needed. In the new criteria, three hierarchical cortisol cutoff values, 5.0, 3.0 and 1.8 μg/dL, after a 1-mg DST are presented. Serum cortisol ≥5 μg/dL after a 1-mg DST alone is considered sufficient to judge autonomous cortisol secretion for the diagnosis of SCS, and the current criterion based on serum cortisol ≥3 μg/dL after a 1-mg DST can continue to be used. Clinical evidence suggests that serum cortisol ≥1.8-2.9 μg/dL after a 1-mg DST is not always normal, so cases who meet the cutoff value as well as a basal adrenocorticotropic hormone (ACTH) level <10 pg/mL (or poor ACTH response to corticotropin-releasing hormone (CRH)) and nocturnal serum cortisol ≥5 μg/dL are proposed to have SCS. We suggest surgery if cases show serum cortisol ≥5 μg/dL after a 1-mg DST (or are disheartened by treatment-resistant problems) or suspicious cases of adrenal cancer according to tumor imaging.

Development of a rapid liquid chromatography tandem mass spectrometry method for the quantitation of serum dexamethasone and its clinical verification

Background Measurement of serum dexamethasone during the overnight dexamethasone-suppression test has been recommended to reduce false-positive results when investigating Cushing's syndrome or increasingly commonly found adrenal incidentalomas. Despite this, there remains a paucity of well-validated dexamethasone methods currently available. Here, we describe the development of a rapid and sensitive liquid chromatography tandem mass spectrometry serum dexamethasone assay and verify its utility in a cohort of postmenopausal females. Method Isotopically labelled internal standard was added to samples prior to supported liquid extraction. Extracts were analysed using liquid chromatography tandem mass spectrometry in the positive electrospray ionization mode. Multiple reaction monitoring was used to detect dexamethasone and its corresponding internal standard transitions. Normal healthy postmenopausal women ( n = 95) were recruited and underwent an overnight dexamethasone suppression test, with serum dexamethasone and cortisol measurements at 09:00 after administration of oral dexamethasone 1 mg at 23:00 the night before. Results Mean intra- and inter-assay imprecision were 4.1% and 2.9%, respectively, for dexamethasone concentrations of 1.5, 6.0 and 12.0 nmol/L. Matrix effects were found to be negligible at 106-109% with recovery ranging from 96 to 100%. The limit of quantitation was 0.25 nmol/L, and structural analogue analysis proved the method to be robust against interferences. Applying a serum dexamethasone cut-off of >3.3 nmol/L was associated with a serum cortisol ≤50 nmol/L in 84/95 individuals. Conclusion We have developed a sensitive and robust liquid chromatography tandem mass spectrometry method for the quantitation of serum dexamethasone. The method can be used to identify false-positive results during the overnight dexamethasone suppression test or for pharmacokinetic studies.