POMC and Cowden syndrome 1: Ceccato et al performed a meta-analysis of 43 studies which reported the use of HDDST, comprising over 3000 patients with ACTH-dependent CS, and the most commonly used schedules were 8-mg overnight HDDST or 2 mg of dexamethasone 6-hourly for 2 days (48-hour HDDST); the overall sensitivity and specificity of the serum cortisol suppression after HDDST were 81% and 84%, respectively, in differentiating CD from EAS [28].