Predictors for future cystic fibrosis-related diabetes by oral glucose tolerance test

J Cyst Fibros. 2014 Jan;13(1):80-5. doi: 10.1016/j.jcf.2013.06.001. Epub 2013 Jun 25.


Background: An annual oral glucose tolerance test (OGTT) has become part of standard care in cystic fibrosis (CF) to screen for CF-related diabetes (CFRD). The objective of this study was to determine predictors for future CFRD derived from an OGTT.

Methods: Data were collected from 2001 to 2009 during a longitudinal prospective study on "Early Diagnosis of Diabetes Mellitus in CF Patients, trial number NCT00662714". 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 -- INDET) and those with a lower level (no-INDET). Logistic regression analysis was used to identify predictors from the first OGTT for future diabetes.

Results: 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).

Conclusions: 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.

Keywords: Cystic fibrosis; Cystic fibrosis-related diabetes; Oral glucose tolerance test.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Child
  • Cystic Fibrosis / epidemiology*
  • Diabetes Mellitus / diagnosis*
  • Diabetes Mellitus / epidemiology*
  • Early Diagnosis
  • Female
  • Glucose Intolerance / diagnosis
  • Glucose Intolerance / epidemiology
  • Glucose Tolerance Test*
  • Humans
  • Incidence
  • Logistic Models
  • Longitudinal Studies
  • Male
  • Practice Guidelines as Topic
  • Prediabetic State / diagnosis
  • Prediabetic State / epidemiology
  • Predictive Value of Tests
  • Prospective Studies
  • Risk Factors
  • Young Adult

Associated data