LAUSR

BACKGROUND The 0.25mg short synacthen test (SST) is used to assess recovery from hypothalamic-pituitary-adrenal (HPA) suppression due to chronic glucocorticoid administration. We assessed the potential role of salivary cortisol and cortisone in predicting HPA function using the SST as the gold standard test. METHOD Between 09:00 and 10:30 salivary and blood samples were collected just prior to a SST to assess HPA axis recovery in patients previously treated with oral glucocorticoids. The cut-off for a normal SST was a 30-minute cortisol â¥450nmol/L. RESULTS Fifty-six SSTs were performed on 47 patients. Of these, 15 were normal. The area under receiver operating characteristic (ROC) curves for serum cortisol, salivary cortisone and salivary cortisol were 0.772, 0.785 and 0.770 respectively. From the ROC analysis, the cut-offs for baseline serum cortisol (â¥365nmol/L) and salivary cortisone (â¥37.2nmol) predicted HPA axis recovery with 100% specificity in 26.7% of pass SSTs; whereas salivary cortisol predicted none. Baseline serum cortisol (â¤170nmol/L), salivary cortisone (â¤9.42nmol/L) and salivary cortisol (â¤1.92nmol/L) predicted HPA suppression with 100% sensitivity in 58.5%, 53.7% and 51.2% of failed SSTs respectively. Using these cut-offs, baseline serum cortisol, salivary cortisone and salivary cortisol could reduce the need for SSTs by 50%, 46% and 37% respectively. CONCLUSION Although marginally inferior to early morning serum cortisol, early morning salivary cortisone may be used as a first-line test for assessing HPA function. We plan to incorporate salivary cortisone into a home based patient pathway to identify patients with HPA recovery, continuing HPA suppression and those who require a SST.