Urinary free cortisol measurement most accurate first-line test for Cushing’s syndrome diagnosis

Posted on August 19, 2015 by MaryO

ufc

 

Ceccato F, et al. J Clin Endocrinol Metab. 2015;doi:10.1210/jc.2015-2507.

Measuring 24-hour urinary free cortisol with liquid chromatography-mass spectrometry is the most accurate first-line diagnostic tool for diagnosing Cushing’s syndrome in adults, according to research published in The Journal of Clinical Endocrinology & Metabolism.

Filippo Ceccato, MD, of the University Hospital of Padova, Italy, and colleagues analyzed data from 137 adults from 2012 to 2014 (108 women; mean age, 41 years) with clinical conditions suggestive of hypercortisolism. Within the cohort, 38 had a confirmed diagnosis of Cushing’s syndrome (27 women); 99 did not have the diagnosis. In all patients, researchers measured 24-hour urinary free cortisol with liquid chromatography-tandem mass spectrometry (LC-MS/MS), late-night salivary cortisol with a radio-immunometric method and serum cortisol with a 1-mg dexamethasone suppression test. Researchers performed all three tests on patients within 2 weeks to avoid fluctuations in cortisol production.

Researchers found that using LC-MS/MS to measure urinary free cortisol revealed both a combined higher positive ratio (10.7) and a lower negative likelihood ratio (0.03) among the three first-line tests.

For the 1-mg dexamethasone suppression test, researchers found a cutoff of 138 nmol/L revealed the best specificity (97%), whereas the 50 nmol/L cutoff confirmed the best sensitivity (100%). For the late-night salivary cortisol test, researchers found a cutoff of 14.46 provided a sensitivity of 84% and specificity of 89%. For urinary free cortisol, a cutoff of 170 nmol during 24 hours provided a sensitivity of 97% and specificity of 91%.

After using a receiver operating characteristic (ROC)-contrast analysis to compare the power of each test alone and combined with one another, the urinary free cortisol assay was at least as good as all the other possible combinations, according to researchers.

“This result is rather surprising because some authors have recently advocated replacing [the urinary free cortisol] assay with other tests,” the researchers wrote. “Our findings go against such a hypothesis, probably because we used LC-MS/MS in our routine clinical practice for all patients, meaning that high [urinary free cortisol] concentrations pointed to a high likelihood of [Cushing’s syndrome].”

Researchers also observed higher urinary free cortisol levels in men with Cushing’s syndrome, as well as greater cortisol suppression in the 1-mg dexamethasone suppression test in women, but noted that sex did not affect the diagnostic accuracy of tests.

“Choosing between valid tests for ruling out [Cushing’s syndrome] in high-risk populations requires an understanding of their diagnostic performance in different clinical settings,” the researchers wrote. “We recommend measuring [urinary free cortisol] with LC-MS/MS as the first-line screening test for the diagnosis of [Cushing’s syndrome], and then confirming hypercortisolism with the 1-mg [dexamethasone suppression test] or late-night salivary cortisol assay.” – by Regina Schaffer

Disclosure: The researchers report no relevant financial disclosures.

From http://www.healio.com/endocrinology/adrenal/news/online/%7B1851a57b-4e76-4c5d-ad7e-ef217c2a2336%7D/urinary-free-cortisol-measurement-most-accurate-first-line-test-for-cushings-syndrome-diagnosis

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Does a Normal Urine Free Cortisol Result Rule out Cushing’s Syndrome?

Posted on August 4, 2015 by MaryO
Endocrine Society’s 97th Annual Meeting and Expo, March 5–8, 2015 – San Diego
SAT-384:
Does a Normal Urine Free Cortisol Result Rule out Cushing’s Syndrome?
Susmeeta T. Sharma1 and Lynnette K Nieman2

  • 1Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
  • 2National Institutes of Health, Bethesda, MD
Presentation Number: SAT-384
Date of Presentation: March 7, 2015
Abstract:Background: Urine free cortisol (UFC) has been traditionally used as one of the first steps in the diagnostic evaluation of Cushing’s syndrome (CS) (1). False positive results, especially values less than twice the upper limit of normal (ULN), can be seen in uncontrolled diabetes, obesity, depression, alcoholism, increased fluid intake, overcollection and stress. False negative results have also been reported with incomplete collection, in mild or cyclic CS and in patients with renal insufficiency (2-3). We evaluated the diagnostic accuracy of UFC and 24-hour urine 17-hydroxycorticosteroids (17OHCS) in patients with CS.Methods: Retrospective study of all CS patients evaluated at the National Institutes of Health (NIH) from 2009 to 2014. Screening tests used for CS included UFC, 17OHCS, late night salivary cortisol (LNSC), midnight serum cortisol and low dose (1mg overnight or 2-day 2mg/day) dexamethasone suppression test (DST). Values above reference range for UFC, 17OHCS and LNSC, a midnight serum cortisol ≥ 7.5 mcg/dL, and post-dexamethasone cortisol values ≥ 1.8 mcg/dL were considered abnormal. Hourly 24-hour sampling for cortisol was performed in a few cases with a mild clinical phenotype and equivocal test results. UFC was measured using liquid chromatography/tandem mass spectrometry (LC-MS/MS). 17OHCS was measured using colorimetric methodology with Porter-Silber reaction (reported as mg/g of creatinine). Mean of the first two UFC and 17OHCS values (appropriate collection by urine volume and creatinine) obtained within 30 days of initial NIH presentation were used for the purpose of this study.

Results: Seventy-two patients were diagnosed with CS (aged 18-77 years, 51 females). Of these, 51 had Cushing’s disease (CD), 10 had ectopic CS while 2 had an adrenal source of Cushing’s based on pathology. Biochemical tests including inferior petrosal sinus sampling (IPSS) suggested ectopic CS but no tumor was found (occult) in 6 patients. IPSS was indicative of a pituitary source in 2 patients with failed transsphenoidal surgery while one patient did not complete evaluation for ACTH-dependent CS. UFC results were available in all, 17OHCS in 70, LNSC in 21, midnight serum cortisol in 68 and DST results in 37 patients. UFC was falsely normal in six and only minimally elevated (< 2 x ULN) in 13 patients (normal renal function, no history of cyclicity, all had CD). Of these 19 patients, 24h 17OHCS was abnormal in all, LNSC was abnormal in 12, midnight serum cortisol was abnormal in 18 and DST was abnormal in 12 patients. Hourly 24-hour sampling for cortisol performed in 3 of these patients revealed abnormal nadir (> 7.5 mcg/dL) and mean daily serum cortisol (> 9 mcg/dL) levels.

Conclusion: UFC can be falsely normal or only minimally elevated in mild CS. Multiple collections and use of complimentary screening tests including 24-hour urine 17OHCS and LNSC can help make a diagnosis and prevent delay in treatment.

(1) Newell-Price J, et al. Cushing’s syndrome. Lancet. 2006;367(9522):1605-17.  (2) Alexandraki KI, et al. Is urinary free cortisol of value in the diagnosis of Cushing’s syndrome. Curr Opin Endocrinol Diabetes Obes. 2011;18:259–63.  (3) Kidambi S, et al. Limitations of nocturnal salivary cortisol and urine free cortisol in the diagnosis of mild Cushing’s syndrome. Eur J Endocrinol. 2007;157(6):725-31

Nothing to Disclose: STS, LKN

Sources of Research Support: This research was in part supported by the intramural research program of NICHD/NIH

Read the entire article at http://press.endocrine.org/doi/abs/10.1210/endo-meetings.2015.ahpaa.9.sat-384

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A Single Midnight Serum Cortisol Measurement Distinguishes Cushing’s Syndrome from Pseudo-Cushing States

Posted on August 1, 2015 by MaryO
Dimitris A. Papanicolaou, Jack A. Yanovski, Gordon B. Cutler, Jr. 2 , George P. Chrousos, and Lynnette K. Nieman
Address all correspondence and requests for reprints to: Dimitris A. Papanicolaou, M.D., Developmental Endocrinology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Building 10, Room 10N262, 10 Center Drive, MSC 1862, Bethesda, Maryland 20892-1862. E-mail: papanicd@cc1.nichd.nih.gov.
DOI: http://dx.doi.org/10.1210/jcem.83.4.4733
Received: October 22, 1997
Accepted: January 05, 1998
First Published Online: July 01, 2013
Abstract

Cushing’s syndrome (CS) may be difficult to distinguish from pseudo-Cushing states (PCS) based on physical findings or urinary glucocorticoid excretion. As the lack of diurnal variation in serum cortisol is characteristic of CS, we studied whether diurnal cortisol determinations could discriminate CS from PCS. Two hundred and sixty-three patients were evaluated: 240 had CS, and 23 had PCS. Urine was collected for 24 h for measurement of cortisol and 17-hydroxycorticosteroids (17OHCS). Blood was drawn at 2300, 2330, 0000, 0030, and 0100 h and at 0600, 0630, 0700, 0730, and 0800 h the next morning for serum cortisol determination. The main outcome measure was the sensitivity of these parameters for the diagnosis of CS at 100% specificity. A midnight cortisol value greater than 7.5 μg/dL correctly identified 225 of 234 patients with CS and all PCS patients. This sensitivity (96%) was superior to that obtained for any other measure, including urinary cortisol (45%), 17OHCS (22%), any other individual cortisol time point (10–92%), the morning (23%) or the evening (93%) cortisol mean, and the ratio (11%) of morning to evening values. We conclude that at 100% specificity, a single serum cortisol value above 7.5 μg/dL at midnight discriminates CS from PCS with higher sensitivity than 24-h urinary cortisol or 17OHCS, or other individual or combined measures of serum cortisol.

OVERPRODUCTION of cortisol is the biochemical hallmark of Cushing’s syndrome (CS) regardless of its etiology and is evidenced by increased urinary cortisol excretion, and a decrease in the circadian variation of serum cortisol (1).

Pseudo-Cushing states (PCS), as the name implies, share many of the features of Cushing’s syndrome, including cortisol overproduction. The hypercortisolism of PCS is hypothesized to be caused by increased activity of the CRH neuron, which, in turn, stimulates ACTH production and release (2). PCS are a heterogeneous group of disorders, including chronic alcoholism and alcohol withdrawal syndrome (3, 4), major depression (5), poorly controlled diabetes mellitus (6, 7), and obesity (8). Additionally, transient hypercortisolism may be associated with less obvious psychiatric conditions (e.g. anxiety) in patients with clinical features reminiscent of CS, such as obesity and hypertension, which are common in the general population. The substantial overlap in urinary free cortisol (UFC) excretion and clinical features between some patients with CS and those with PCS can make it difficult to distinguish between the two conditions (9). Thus, although persistent elevation of 24-h UFC in the presence of unequivocal signs of CS (particularly classic moon facies, prominent centripetal obesity, severe proximal muscle weakness, and violaceous striae) suggest the diagnosis of CS, patients with less obvious signs pose a diagnostic dilemma.

Several tests have been proposed to diagnose CS, including 24-h UFC measurements, the 1-mg overnight dexamethasone suppression test (DST) (10), the 2-day DST (1), and the dexamethasone-CRH (Dex-CRH) stimulation test (8). Each has drawbacks. Twenty-four-hour urinary collections are inconvenient and often incomplete. The 1-mg overnight DST is commonly used as a screening test to exclude the diagnosis of CS. This test has two caveats. First, a criterion for the level of serum cortisol suppression to exclude CS has not been developed using modern RIAs. Second, although the test has a false negative rate of only 2%, it has a significant false positive rate, especially in chronically ill (23%) or obese patients (13%) (11) and in patients with major depression (43%) or other psychiatric disorders (8–41%) (12). Even in normal individuals, the test may be consistent with CS in up to 30% (9).

Similarly, the 2-mg 2-day DST, often used as a confirmatory diagnostic test, has a diagnostic accuracy of only 71% (8). An additional problem is the variable metabolic clearance of dexamethasone (13), which is especially problematic in patients receiving medications that induce the cytochrome P450-related enzymes (e.g.phenytoin, rifampin, and phenobarbital) (14) or in patients with renal or hepatic failure. In such cases, neither DST gives reliable results. Finally, the drawbacks of 24-h urine collections apply to the DST as well.

We previously determined that the dexamethasone-CRH test has a diagnostic accuracy of 98% in the distinction of CS from PCS (8, 15). However, although accurate, this test has the drawbacks related to dexamethasone clearance, as discussed above.

Physiological cortisol secretion is characterized by circadian rhythmicity. Serum cortisol concentration reaches its zenith in the morning (0600–0800 h) and its nadir in the night during the first half of normal sleep. Krieger et al. defined the normal circadian rhythm of plasma corticosteroid levels as the pattern where all plasma glucocorticoid levels from 1600–2400 h were 75% or less of the 0800 h value (16). As previous studies have found that obese individuals retain a normal circadian cortisol rhythm (17), we hypothesized that differences in circadian plasma cortisol values would distinguish CS from PCS. To test this hypothesis, we prospectively measured serum cortisol values during the normal nadir and zenith periods in patients being evaluated for CS.

Read the entire study at http://press.endocrine.org/doi/10.1210/jcem.83.4.4733?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub%3Dpubmed

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Lowest cortisol levels found in women with overweight, mild obesity

Posted on July 18, 2015 by MaryO

Women with overweight and class I obesity appear to have the lowest cortisol levels, while more significant obesity appears to be associated with higher cortisol levels, according to recent findings.

In the cross-sectional study, Karen K. Miller, MD, of Massachusetts General Hospital, and colleagues evaluated 60 premenopausal women aged 18 to 45 years: 28 with overweight or obesity, 18 with anorexia nervosa and 21 healthy controls at normal weight. Overweight was defined as BMI 25 to 29.9 kg/m2, and obesity was classified as class I (30-34.9 kg/m2) and class II (35-39 kg/m2).

Anorexia nervosa was classified based on DSM-IV criteria, which includes extreme fear of weight gain, body image dysmorphia, weight that is 85% of ideal body weight and cessation of menstruation for 3 consecutive months. Participants were asked to collect 24-hour urine samples, in addition to 11 p.m. and 7 a.m. salivary samples within 1 week of an inpatient hospital visit. For each sample, researchers assessed creatinine clearance, and urinary free cortisol/creatinine clearance was calculated for each specimen to account for the decreased creatinine and filtered cortisol linked to anorexia nervosa.

During the inpatient visit, participants underwent placement of an IV catheter and fasting blood was sampled every 20 minutes from 8 p.m. to 8 a.m. Fasting cortisol and cortisol binding globulin concentrations were measured at 8 a.m. Participants were asked to take 5 g of oral dexamethasone every 6 hours for 48 hours to decrease endogenous disparities in cortisol levels.

The researchers found that with the exception of dexamethasone-suppression-CRH testing, all cortisol measures exhibited a U-shaped association with BMI, most notably urinary free cortisol/creatinine clearance (P = .0004) and mean overnight serum cortisol (P < .0001).

The lowest cortisol levels were seen in the overweight-class I obesity range, and these were also associated with visceral fat tissue and total fat mass. Participants with anorexia nervosa had higher mean cortisol levels than participants with overweight or obesity. Attenuated inverse relationships were seen between lean mass and some measures of cortisol, and most measures of cortisol were inversely related to posterior-anterior spine and total hip bone mineral density.

According to the researchers, these findings have not determined the precise nature of the relationship between cortisolemia, hypothalamic-pituitary-adrenal activation and adiposity.

“The [hypothalamic-pituitary-adrenal] axis activation associated with obesity and excess adiposity raises the question of whether hypercortisolemia contributes to increased adiposity in the setting of caloric excess, whether increased adiposity drives [hypothalamic-pituitary adrenal] activation, or whether the relationship between hypercortisolemia and adiposity is bidirectional,” the researchers wrote. – by Jennifer Byrne

Disclosure: The researchers report no relevant financial disclosures.

From http://www.healio.com/endocrinology/obesity/news/online/%7B73cac1c4-af30-4f24-89e3-86f50d05aaa2%7D/lowest-cortisol-levels-found-in-women-with-overweight-mild-obesity

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The low-dose dexamethasone suppression test: a reevaluation in patients with Cushing’s syndrome

Posted on July 9, 2015 by MaryO

J Clin Endocrinol Metab. 2004 Mar;89(3):1222-6.

Findling JW1, Raff H, Aron DC.

Abstract

Low-dose dexamethasone suppression testing has been recommended for biochemical screening when Cushing’s syndrome is suspected. The criterion for normal suppression of cortisol after dexamethasone is controversial.

To assess diagnostic utility (sensitivity), we report the results of low-dose dexamethasone suppression testing in 103 patients with spontaneous Cushing’s syndrome. There were 80 patients with Cushing’s disease (78%), 13 with the ectopic ACTH syndrome (13%), and 10 with cortisol-producing adrenocortical adenomas (10%). Fourteen (18%) of 80 patients with Cushing’s disease suppressed serum cortisol to less than 5 micro g/dl (<135 nmol/liter) after the overnight 1-mg test, whereas six patients (8%) actually showed suppression of serum cortisol to less than 2 micro g/dl (<54 nmol/liter). In addition, the 2-d, low-dose dexamethasone suppression test yielded false-negative results in 38% of patients when urine cortisol was used and 28% when urinary 17-hydroxycorticosteroids were used. Serum cortisol after the 1-mg test correlated with baseline urinary free cortisol (r = 0.705, P < 0.001), plasma ACTH level (r = 0.322, P = 0.001), and urinary free cortisol after the 2-d test (r = 0.709, P = 0.001).

This study provides evidence that low-dose dexamethasone may suppress either plasma cortisol or urinary steroids to levels previously thought to exclude Cushing’s syndrome and that these tests should not be used as the sole criterion to exclude the diagnosis of endogenous hypercortisolism.

PMID:
15001614
[PubMed – indexed for MEDLINE]

From http://www.ncbi.nlm.nih.gov/pubmed/15001614

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