Screening for Cystic Fibrosis-Related Diabetes: Matching Pathophysiology and Addressing Current Challenges

Nearly 50% of adult patients with cystic fibrosis (CF) have diabetes. The occurrence of CF-related diabetes (CFRD) is preceded and is associated with deterioration of lung function and nutritional status. Microvascular complications can occur, but the main cause of death is respiratory failure rather than cardiovascular causes as in type 1 or type 2 diabetes. Because other methods such as glycated hemoglobin (A1C) levels are less sensitive in patients with CF, the recommended screening test is the oral glucose tolerance test (OGTT) with a 75 g glucose dose. However, OGTT is poorly suited for patients with CF, who are already facing a high disease-care burden, and appropriate CF-glucose cut-off for diagnosis and prognosis are also questioned. Thus, alternative screening methods are compared to the classical test (2-hour OGTT), including shorter OGTTs and continuous glucose monitoring. Moreover, many challenges complicate the screening for diabetes such as the complex medical care time for a patient, which is reflected by low adherence to screening tests. The best screening test should take into account the particularities of CFRD and the complexity of the CF medical care.