Scalp hair cortisol measurement is an accurate first-line diagnostic test for Cushing’s syndrome in adults and offers several advantages over other first-line diagnostic procedures, according to findings published in the European Journal of Endocrinology.
“[Hair cortisol content] has practical advantages over currently used diagnostic tests, since sample collection can easily be performed in an outpatient setting and is not dependent on patient adherence to sampling instructions,” Elisabeth F. C. van Rossum, MD, PhD, professor at Erasmus MC, University Medical Center Rotterdam in the Netherlands, and colleagues wrote. “Furthermore, [hair cortisol content] measurement offers retrospective information about cortisol levels over months of time in a single measurement, thereby potentially circumventing the limitations posed by the variability in cortisol secretion in endogenous [Cushing’s syndrome].”
Van Rossum and colleagues analyzed data from 43 patients with confirmed endogenous Cushing’s syndrome and 35 patients with suspected Cushing’s syndrome in whom diagnosis was excluded after testing (patient controls), all evaluated between 2009 and 2016 at an endocrinology outpatient clinic at Erasmus MC. Adults from a previously published validation study served as healthy controls (n = 174). Researchers measured scalp hair samples, 24-hour urinary free cortisol, serum cortisol and salivary cortisol, and used Pearson’s correlation to determine associations between hair cortisol content and first-line screening tests for Cushing’s syndrome.
Hair cortisol content was highest in patients with Cushing’s syndrome (geometric mean, 106.9 pg/mg; 95% CI, 77.1-147.9) and higher compared with both healthy controls (mean, 8.4 pg/mg; 95% CI, 7-10) and patient controls (mean, 12.7 pg/mg; 95% CI, 8.6-18.6). Using healthy controls as the reference population, researchers found that the optimal cutoff for diagnosis of Cushing’s syndrome via hair cortisol content was 31.1 pg/mg; sensitivity and specificity were 93% and 90%, respectively (area under the curve = 0.958). Results were similar when using patient controls as the reference population, according to the researchers.
Hair cortisol content was correlated with urinary free cortisol (P < .001), serum cortisol (P < .001) and late-night salivary cortisol (P < .001). In addition, in two patients with ectopic Cushing’s syndrome, researchers observed a gradual rise in hair cortisol content in the 3 to 6 months before disease diagnosis.
“Together with a straightforward sample collection procedure, this method may prove to be a convenient noninvasive screening test for [Cushing’s syndrome],” the researchers wrote. “Additionally, our results indicate that hair cortisol measurements provide clinicians a tool to retrospectively assess cortisol secretion in patients with [Cushing’s syndrome], months to years back in time. This also offers the opportunity to estimate the onset of hypercortisolism and thus the duration of the disease before diagnosis.” – by Regina Schaffer
Disclosure: The researchers report no relevant financial disclosures.