Cushing’s Syndrome Epidemiology

By Yolanda Smith, BPharm

Cushing’s syndrome is considered to be a rare disorder that results from prolonged exposure to glucocorticoids. However, there are few epidemiological studies to provide adequate data to describe the incidence and prevalence of the condition accurately. Most cases are diagnosed between the ages of 20 and 50, although any individual may be affected at any age.

The presentation of the symptoms of Cushing’s syndrome can vary greatly. In addition, many of the symptoms overlap with those caused by other health conditions, such as metabolic syndrome and polycystic ovary syndrome. This can make the diagnosis of the condition difficult. It is also difficult to establish epidemiological trends in Cushing’s syndrome, because not all cases of the disease are diagnosed. However, it is important that diagnosis is made as soon as possible, because early diagnosis and treatment of the condition are associated with improved morbidity and mortality rates.

Population-based Studies

There are several population-based studies that have reported the incidence and mortality rates of Cushing’s syndrome in certain populations over a discrete period of time.

A study in Denmark followed 166 patients with Cushing’s syndrome for 11 years, finding an incidence of 2 cases per million population per year. Of the 166 patients, 139 had benign disease. There was a mortality rate of 16.5% in the follow-up period of 8 years, with most deaths occurring in the year after the initial diagnosis, often before the initiation of treatment. The causes of death of patients with Cushing’s syndrome in the study included severe infections, cardiac rupture, stroke and suicide.

A study in Spain found 49 cases of Cushing’s syndrome over a period of 18 years, with an incidence of 2.4 cases per million inhabitants per year and a prevalence of 39.1 cases per million. The standard mortality ratio in this study was 3.8, in addition to an increase in morbidity rates.

Incidence

A low incidence of endogenous Cushing’s syndrome was established by the population-based studies outlined above, corresponding to approximately 2 cases per million. Some studies have an estimated incidence as low as 0.7 people per million.

However, the incidence of subclinical Cushing’s syndrome may be underestimated in certain population groups, such as those with osteoporosis, uncontrolled diabetes mellitus or hypertension. For example, of 90 obese patients with uncontrolled diabetes mellitus in one study, three had Cushing’s syndrome. This yielded a prevalence of 3.3%, which is considerably higher than the incidence reported in the population-based studies. However, these findings should be supported by larger studies.

Females are more likely to be affected by Cushing’s syndrome than males, with a risk ratio of approximately 3:1. There does not appear to be a genetic link that involves an ethnic susceptibility to the condition.

Treatment Outcomes

Surgery is the first-line treatment option for most cases of overt disease and remission is achieved in the majority of patients, approximately 65-85%. However, for up to 1 in 5 patients the condition recurs, and the risk does not appear to level off, even after 20 years of follow-up.

The risk of mortality for individuals with Cushing’s syndrome is estimated to be 2-3 times higher than that of the general population, based on epidemiological studies.

Reviewed by Dr Liji Thomas, MD.

From http://www.news-medical.net/health/Cushings-Syndrome-Epidemiology.aspx

Cushing’s: Update on signs, symptoms and biochemical screening

10.1530/EJE-15-0464

  1. Lynnette Nieman

+Author Affiliations


  1. L Nieman, RBMB, NIH, Bethesda, 20817-1109, United States
  1. Correspondence: Lynnette Nieman, Email: niemanl@mail.nih.gov

Abstract

Endogenous pathologic hypercortisolism, or Cushing’s syndrome, is associated with poor quality of life, morbidity and increased mortality. Early diagnosis may mitigate against this natural history of the disorder.

The clinical presentation of Cushing’s syndrome varies, in part related to the extent and duration of cortisol excess. When hypercortisolism is severe, its signs and symptoms are unmistakable. However, most of the signs and symptoms of Cushing’s syndrome are common in the general population (e.g. hypertension and weight gain) and not all are present in every patient.

In addition to classical features of glucocorticoid excess, such as proximal muscle weakness and wide purple striae, patients may present with the associated co-morbidities that are caused by hypercortisolism. These include cardiovascular disease, thromboembolic disease, psychiatric and cognitive deficits, and infections. As a result, internists and generalists must consider Cushing’s syndrome as a cause, and endocrinologists should search for and treat these co-morbidities.

Recommended tests to screen for Cushing’s syndrome include 1 mg dexamethasone suppression, urine free cortisol and late night salivary cortisol. These may be slightly elevated in patients with physiologic hypercortisolism, which should be excluded, along with exogenous glucocorticoid use. Each screening test has caveats and the choice of tests should be individualized based on each patient’s characteristics and lifestyle.

The objective of this review was to update the readership on the clinical and biochemical features of Cushing’s syndrome that are useful when evaluating patients for this diagnosis.

Read the entire manuscript at http://www.eje-online.org/content/early/2015/07/08/EJE-15-0464.full.pdf+html

Hair Analysis Provides a Historical Record of Cortisol Levels in Cushing’s Syndrome

Exp Clin Endocrinol Diabetes. Author manuscript; available in PMC 2010 Sep 24.
Published in final edited form as:
PMCID: PMC2945912
NIHMSID: NIHMS235640
Hair Analysis Provides a Historical Record of Cortisol Levels in Cushing’s Syndrome

Abstract

The severity of Cushing’s Syndrome (CS) depends on the duration and extent of the exposure to excess glucocorticoids. Current measurements of cortisol in serum, saliva and urine reflect systemic cortisol levels at the time of sample collection, but cannot assess past cortisol levels. Hair cortisol levels may be increased in patients with CS, and, as hair grows about 1 cm/month, measurement of hair cortisol may provide historical information on the development of hypercortisolism.

We attempted to measure cortisol in hair in relation to clinical course in six female patients with CS and in 32 healthy volunteers in 1 cm hair sections. Hair cortisol content was measured using a commercially available salivary cortisol immune assay with a protocol modified for use with hair.

Hair cortisol levels were higher in patients with CS than in controls, the medians (ranges) were 679 (279–2500) and 116 (26–204) ng/g respectively (P <0.001). Segmental hair analysis provided information for up to 18 months before time of sampling. Hair cortisol concentrations appeared to vary in accordance with the clinical course.

Based on these data, we suggest that hair cortisol measurement is a novel method for assessing dynamic systemic cortisol exposure and provides unique historical information on variation in cortisol, and that more research is required to fully understand the utility and limits of this technique.

Keywords: glucocorticoids, pituitary adenoma, cancer, adrenal gland, hormones, cushing hair

Crooke’s changes common in patients with Cushing’s syndrome, high cortisol production

 

Evidence of Crooke hyaline changes in the pituitary gland points to a higher likelihood of Cushing’s syndrome in adults, with the changes in basophil cells occurring in 75% to 80% of patients with the hormonal disorder, according to research in The Journal of Clinical Endocrinology & Metabolism.

In a retrospective review of hospital patient records from adults with Cushing’s syndrome who underwent pituitary surgery, researchers also found that a higher degree of cortisol production, as well as exposure to excess glucocorticoids, are often associated with Crooke’s changes in adults.

“The presence of Crooke’s changes is a clear indication of the presence of Cushing’s syndrome, although the absence of Crooke’s changes does not exclude it,” the researchers wrote.

Edward H. Oldfield, MD, FACS, of the department of neurological surgery at University of Virginia Health System, and colleagues analyzed electronic hospital data from 213 consecutive patients with Cushing’s syndrome who received pituitary surgery between 2008 and March 2014. Researchers reviewed analysis of the normal pituitary tissue included with the specimens obtained at surgery, as well as cortisol production measured by 24-hour urine.

Within the cohort, Crooke’s changes occurred in 74% of patients; Crooke’s changes occurred in 81% of patients with an adrenocorticotropic hormone tumor.

Researchers also found that 91% of patients with an adrenocorticotropic hormone-producing tumor and a urinary free cortisol test at least fourfold the upper limit of normal had evidence of Crooke’s changes vs. 74% of patients with a urine cortisol amount that was less than fourfold the upper limit of normal (P = .008).

“Our results clearly demonstrate a correlation between the degree of cortisol production and the presence of Crooke’s changes,” the researchers wrote. “Patients with cortisol production exceeding fourfold upper limit almost all had Crooke’s changes.”

Researchers said study results indicate that the presence of Crooke’s changes may be used to indicate that a patient has Cushing’s syndrome following a pituitary surgery in which no tumor is found.

“However, the absence of Crooke’s changes does not reliably indicate the absence of Cushing’s syndrome, as 19% of patients with a proven [adrenocorticotropic hormone-producing tumor] did not have Crooke’s changes,” the researchers wrote. by Regina Schaffer

Disclosure: The researchers report no relevant financial disclosures.

From http://www.healio.com/endocrinology/adrenal/news/online/%7B838a3557-f284-4fda-b93d-73dbb4823667%7D/crookes-changes-common-in-patients-with-cushings-syndrome-high-cortisol-production

Cushing’s Syndrome

Prof André Lacroix, MDcorrespondence,  Richard A Feelders, MD, Constantine A Stratakis, MD, Lynnette K Nieman, MD