Endocrine Abstracts

The risks of over and under-replacement with glucocorticoid replacement therapy are well-known. In an attempt to minimise these risks cortisol day curves (CDC) are performed in many centres, however there is a dearth of data on the reproducibility of this assessment and the relationship between symptoms and serum cortisol levels. To address these issues, we have performed 2 cortisol day curves within 7 days in 20 patients (9 male, mean age 54 years, range 25-79, 6 primary and 14 secondary adrenal failure) on long- term hydrocortisone (HC) replacement therapy; the total daily dose was 20/30 milligrams divided into twice or three times daily at standard times. Serum cortisol was measured prior to the first dose of HC at 09.00, then at 30 minute intervals for 90 minutes, and hourly intervals until 20.30. 24 hour urinary free cortisol (UFC) was measured from 09.00 to 09.00, the following day. Simultaneous with each blood sample patients completed visual analogue scales (VAS) for tiredness, energy levels, and well-being. The median peak morning serum cortisol was 640.5 nanomole per litre (range 411-921) and occurred 90 minutes (range 30-120) after the dose. The median AUC and UFC were 3346 (range 2166-5441) nanomole per litre /11.5 hours and 155 (range 28-538) nanomole per litre respectively. Comparison of AUC, maximum and minimum serum cortisol, UFC for the 2 CDC were within 10% of each other in 12, 9, 7, 4 patients and within 20% of each other in 16, 15, 14, 6 patients respectively. There was no significant correlation between serum cortisol and VAS for tiredness, energy levels, and well-being. The reproducibility of the CDC is acceptable but the relationship of serum cortisol to symptoms requires further exploration