Endocrine Abstracts

Mrs. M is a 66-year-old female who has had secondary adrenal insufficiency for many years following the withdrawal of prednisolone therapy for pulmonary eosinophilia. Synacthen tests revealed complete adrenal suppression when the dose of prednisolone was weaned to 5 mg in previous years. The dose was further reduced by switching to hydrocortisone three times daily, following a 10 mg-5 mg-5 mg regimen. Occasionally, a flare of eosinophilia required restarting high-dose prednisolone, but she had become accustomed to cutting the dose as needed, and then switching to hydrocortisone. She has since developed osteoporosis.

She wanted to compare the effects of prednisolone 3 mg daily, which she had been weaned to during her most recent review, and the hydrocortisone regimen. She experienced no difference in symptoms of withdrawal between the two treatments. Carboxylated osteocalcin (Gla-OC) is an osteoblast-specific product and a marker of bone formation. Gla-OC concentrations were measured at various time points during the day on each treatment, accounting for the diurnal variation.

There was no significant difference between the mean Gla-OC concentration measured 2, 4, 6 and 8 hours after the morning dose of prednisolone (8.25 ng/ml) and hydrocortisone (7.73 ng/ml). Gla-OC was also measured 9 and 10 hours after the morning dose of hydrocortisone (see table 1).

Suppression of bone formation may be reflected by Gla-OC levels, and such levels have the potential to be used to monitor bone formation in patients treated with glucocorticoids, guiding the choice of medication. Long-term follow-up of the patient’s bone mineral density would be necessary to investigate the correlation between Gla-OC and osteoporosis.