First, are these results believable, given the rarity of the Cushing syndrome? The 3.3% prevalence of subclinical hypercortisolism in patients with suspected idiopathic osteoporosis is surprisingly high. Clinically apparent Cushing syndrome is rare, being diagnosed in 0.7 to 2.4 per 1 million persons annually (2). As a result, until recently, clinically inapparent hypercortisolism has not been considered as an important—and potentially reversible—cause of disorders associated with hypercortisolism. However, studies of patients with diabetes, hypertension, and hirsutism showed a prevalence of the Cushing syndrome of 2% to 4%, 1%, and 0.25%, respectively. In light of these relatively high prevalences and the findings reported by Chiodini and colleagues, it seems reasonable to screen patients with these disorders for hypercortisolism and perhaps even investigate the prevalence of pathogenic Cushing syndrome in patients with other signs of the syndrome, such as osteoporosis (3 - 5).