Hair cortisol content in patients with adrenal insufficiency on hydrocortisone replacement therapy

Objective Patients with adrenal insufficiency (AI) require life-long replacement therapy with exogenous glucocorticoids. Several studies have shown impaired subjective health status in these patients as well as increased morbidity and mortality risk, which may be caused by glucocorticoid over-replacement. As a measure of long-term cortisol exposure, the usefulness of hair cortisol analysis in patients receiving glucocorticoid replacement therapy was investigated. Patients and design Hair samples, demographics, medical history and perceived stress scale questionnaires were collected from 93 patients across North America diagnosed with primary or secondary AI. Sixty-two household partners served as a control group. Cortisol was measured in the proximal 2 cm of hair, representing the most recent 2 months of exposure. A modified enzyme immunoassay was used for the measurement of cortisol. Results The male patients had significantly higher hair cortisol levels than the male controls (P < 0·05), while there was no significant difference among females. Hair cortisol content correlated significantly with glucocorticoid dose (r = 0·3, P < 0·01). Patients with AI had significantly higher subjective stress scores than control subjects. Conclusions Hair cortisol content correlates with hydrocortisone (HC) dose in patients with AI. Our results suggest that some AI patients may be over-treated and hence may be at risk for the adverse effects of cortisol. Measurement of HC in hair may become a useful monitoring tool for long-term cortisol exposure in patients treated with glucocorticoids.