Pros and cons of large scale screening of Cushing's syndrome
A Tabarin & P Perez
Data from the literature suggest that endogenous Cushings syndrome (CS) is an unusual disorder in the general population with a reported incidence of 23 cases per 1 million inhabitants per year. Patients who are not cured from CS have a poor prognosis with an increased mortality due to cardiovascular disease and significant morbidity that impairs quality of life. Recently published screening studies performed in obese patients with type 2 diabetes or patients with osteoporosis reported an unexpectedly high prevalence (29%) of occult CS. These data raise the question of the possible relevance of screening for CS in high-risk populations who have clinical conditions that may be caused by hypercortisolism. However, such strategy has to be carefully weighted, considering the extremely elevated number of patients with these conditions. We examined the question through the methodological framework of indication for screening applied to data currently available in the literature. The indication for screening must consider the frequency of the disease and the accuracy of diagnostic methods and balance the severity of untreated disease with the benefit/risk ratio of the whole screening strategy and its consequences including interventions. In this perspective it should be emphasized that screening studies have revealed that a number of patients with occult CS have mild hypercortisolism that is due to moderately hyperactive and autonomous adrenal tumors. In such patients, the biological definition of CS is controversial and no single criteria with accurate diagnostic performances can be easily used for screening purposes. In addition, the role of mild occult CS in the pathogenesis of type 2 diabetes and osteoporosis remains controversial since no large scale prospective intervention study has been performed to date. The available evidence on these points and the possible needs for additional research will be discussed in the perspective of large scale screening for CS.