title: The use of oral glucose tolerance tests to risk stratify for new-onset diabetes after transplantation: An underdiagnosed phenomenon.
abstract: BACKGROUND
  Fasting glucose measurements are insensitive at detecting new-onset diabetes after transplantation (NODAT) and ignore the diagnosis of impaired glucose tolerance (IGT). Both NODAT and IGT confer a higher risk of developing cardiovascular disease. IGT is also a risk factor for NODAT. The aim of this study was to use an oral glucose tolerance test (OGTT) to risk stratify for NODAT and IGT in renal transplant recipients and to relate cardiovascular and phenotypic risk with glycemic dysregulation.
  
  
  METHODS
  In all, 858 renal transplant recipients are under follow up at the University Hospital of Wales, Cardiff, UK. Excluded patients had pretransplant diabetes (78), NODAT (89), or were transplanted less than six months (47), leaving 646 recipients. All remaining recipients with two fasting blood glucoses between 5.6 and 6.9 mmol/L were invited to have an OGTT. A diagnosis of NODAT, IGT, and impaired fasting glucose (IFG) was based on World Health Organization guidelines.
  
  
  RESULTS
  We identified 134 patients who fulfilled the inclusion criteria, of whom 122 had an OGTT (91% of cohort). In all, 51% of patients were found to have abnormal glucose metabolism: 10% NODAT, 14% combined IGT/IFG, 9% IGT alone, and 18% IFG alone. Clinical phenotype was not predictive of diabetic risk on multivariate analysis.
  
  
  CONCLUSIONS
  Our results confirm fasting glucose underestimates the prevalence of NODAT and ignores the prevalence of IGT. These findings suggest routine use of an OGTT in renal transplant recipients is a valuable clinical tool to risk stratify each patient for the development of NODAT and cardiovascular disease.
authors.affiliation: Nephrology and Transplant Directorate, University Hospital of Wales, Heath Park, Cardiff, UK. sharif_adnan@hotmail.com
authors.forename: Adnan
authors.initials: A
authors.lastname: Sharif
authors.forename: Richard H
authors.initials: RH
authors.lastname: Moore
authors.forename: Keshwar
authors.initials: K
authors.lastname: Baboolal
mesh_terms: D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000175:diagnosis*; D003920:Diabetes Mellitus / Q000175:diagnosis*; D042241:Early Diagnosis; D005260:Female; D005951:Glucose Tolerance Test / Q000379:methods*; D006801:Humans; D016030:Kidney Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D012306:Risk