Mechanisms of glucose intolerance in cystic fibrosis

Aims Although cystic fibrosis‐related diabetes (CFRD), a poor prognostic factor in cystic fibrosis (CF), is characterized by insulinopenia, the role of insulin resistance is unclear. Using a prospective study design, we measured insulin resistance, pancreatic β‐cell function and correlated glycaemic status with clinical parameters. Methods Oral glucose tolerance test was performed in 60 stable adult CF patients. Insulin sensitivity and β‐cell function were measured using the homeostatic model assessment (HOMA2), Stumvoll and oral glucose insulin sensitivity (OGIS) indices. Results Forty‐two (70%) had normal glucose tolerance (NGT), 10 (17%) impaired glucose tolerance (IGT) and eight (13%) CFRD. There was no difference in insulin sensitivity among the three groups (HOMA2: NGT 280, IGT 250, CFRD 339, P = 0.42; Stumvoll: NGT 0.128, IGT 0.126, CFRD 0.129, P = 0.76; and OGIS: NGT 515, IGT 472, CFRD 472, P = 0.12). Pancreatic β‐cell function (CFRD 50% vs. NGT 67%; P