Data were collected from 2001 to 2009 during a longitudinal prospective study on 鈥淓arly Diagnosis of Diabetes Mellitus in CF Patients, trial number NCT00662714鈥? The 1093 patients included in the analysis had at least two valid OGTTs each and no CFRD at the first glucose challenge. Normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and CFRD were defined using WHO criteria. In a subsample of 521 patients, the NGT group was further divided into patients with a 1-hour glucose level > 11.1 mmol/l (indeterminate glucose tolerance 鈥?INDET) and those with a lower level (no-INDET). Logistic regression analysis was used to identify predictors from the first OGTT for future diabetes.
Compared with NGT (n = 838), IFG (n = 70; odds ratio [OR], 95% confidence interval: 2.92, 1.60-5.33) and IGT without IFG (n = 155, OR 2.37, 1.48-3.79) were both significant and independent risk factors for future CFRD. Patients with IGT and IFG (n = 30) had the highest risk (OR 5.30, 2.32-12.10). In the subsample analysis, INDET (n = 116) was associated with a significantly increased risk for future CFRD compared with no-INDET (n = 269; OR 2.81, 1.43-5.51).
In this large study, IFT, IGT, and INDET were all predictors of future CFRD. The OGTT in patients with CF should include a 1-hour post-challenge value.