TOPLINE:
An early serum cortisol concentration of > 237 nmol/L (> 8.6 μg/dL) has been validated as a safe and useful screening test with 100% specificity for predicting recovery of the hypothalamic-pituitary-adrenal (HPA) axis in patients on tapering regimes from long‐term chronic glucocorticoid therapy (CGT).
METHODOLOGY:
- A retrospective review of 250-µg Synacthen test (SST) results performed in patients on tapering CGT doses from a single-center rheumatology department over 12 months.
- A total of 60 SSTs were performed in 58 patients, all in the morning (7-12 AM) after withholding CGT for 48 hours.
- Peripheral blood was sampled for cortisol at baseline, 30 minutes, and 60 minutes.
- Adrenal insufficiency (AI) was defined as a peak serum cortisol concentration.
TAKEAWAY:
- The mean duration of CGT (all prednisolone) was 63 months, prescribed primarily for giant cell arteritis/polymyalgia rheumatica (48%) and inflammatory arthritis (18%), with a mean daily dose of 3.4 mg at the time of SST.
- With the investigators’ previously reported basal serum cortisol concentration of > 237 nmol/L (> 8.6 μg/dL) used to confirm an intact HPA axis, no patient with AI would have been missed, but 37 of 51 (73%) unnecessary SSTs in euadrenal patients would have been avoided.
- A basal serum cortisol concentration of > 227 nmol/L had a specificity of 100% for predicting passing the SST, while a basal serum cortisol concentration of ≤ 55 nmol/L had a 100% sensitivity for predicting failure.
- A mean daily prednisolone dosing at the time of SST in patients with AI was significantly higher than that with normal SSTs (5.7 vs 2.9 mg, respectively; P = .01).
IN PRACTICE:
“This offers a more rapid, convenient, and cost‐effective screening method for patients requiring biochemical assessment of the HPA axis with the potential for significant resource savings without any adverse impact on patient safety,” the authors wrote.
SOURCE:
The study was conducted by Ella Sharma, of the Department of Endocrinology, Royal Victoria Infirmary, Newcastle upon Tyne, UK, and colleagues and published online on May 19, 2024, as a letter in Clinical Endocrinology.
LIMITATIONS:
Not provided.
DISCLOSURES:
Not provided.
A version of this article appeared on Medscape.com.