Suppression Failure of Cortisol Secretion by Dexamethasone May Occur in Glucagon-like Peptide-1 Receptor Agonist-treated Patients with Diabetic Autonomic Neuropathy

Two diabetic women (case 1, 75 years old; case 2, 49 years old) being treated with glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1 RAs) showed no suppression of cortisol secretion on a dexamethasone suppression test (DST). However, its secretion was suppressed after switching from GLP-1 RAs to insulin. We also checked the cortisol secretion by a DST in five consecutive inpatients (case 3-7) being treated with GLP-1 RAs. The coefficients of R-R interval variation at rest and during deep breathing were lower in the two false-positive cases (case 1 and 2) than in the five true-negative cases (case 3-6). GLP-1 RAs can be switched to insulin in order to eliminate the slow absorption effect of dexamethasone by GLP-1 RAs if a DST is planned in diabetic patients receiving GLP-1 RAs.