Yung et al present important data on cystic fibrosis related diabetes (CFRD) and suggest a selective approach for screening and diagnosis.1 Although the majority of patients with CFRD may be identified using this approach, over 8% would remain undiagnosed.

CFRD is associated with substantial morbidity and mortality. Analysis of 21 000 patients followed by the Cystic Fibrosis Foundation Registry shows a sixfold increase in mortality for CFRD with more severe pulmonary disease.2

Once insulin treatment begins, FEV₁ and FVC increase and are comparable to non-diabetic patients by two years. The number of pulmonary infections with Haemophilus influenzae andStaphylococcus aureus fall and body mass index increases sharply within three months of starting …