title: Screening for new-onset diabetes after kidney transplantation: limitations of fasting glucose and advantages of afternoon glucose and glycated hemoglobin.
abstract: BACKGROUND
  The sensitivity of fasting plasma glucose (FPG) in screening for new-onset diabetes after transplantation (NODAT) has been questioned, particularly in the presence of moderate-dose prednisolone, where peak plasma glucose occurs 7 to 8 hr after administration. Oral glucose tolerance testing (OGTT) has been mooted as an alternative but is inconvenient for patients.
  
  
  METHODS
  We compared sensitivity of screening tests for NODAT at 6 weeks, 3 months, and 12 months after kidney transplantation in recipients receiving prednisolone, mycophenolate, and tacrolimus.
  
  
  RESULTS
  At 6 weeks, NODAT (capillary blood glucose [CapBG] ≥11.1 mmol/L, FPG ≥7.0 mmol/L, 2-hr plasma glucose ≥11.1 mmol/L, or glycated hemoglobin [HbA1c] ≥6.5%) was detected in 46% with CapBG versus 12% with OGTT (P=0.013), 4% with HbA1c (P<0.001), and 0% with FPG (P<0.001; n=26). At 3 months, NODAT was present in 14% with HbA1c versus 20% with OGTT (P=0.600) and 2% with FPG (P=0.059; n=50), whereas, at 12 months, NODAT was found in 4% with HbA1c versus 6% with OGTT (P=1.00) and 2% with FPG (P=0.618; n=51). Combining 3- and 12-month data, OGTT recorded NODAT in 14% and impaired glucose tolerance in 28%, whereas HbA1c detected NODAT in 10% and impaired glucose tolerance (from ≥5.7 to <6.5%) in 51%. Employing HbA1c as a screening test and reserving OGTT for those with impaired glucose tolerance would detect NODAT with a sensitivity more than 94%, avoiding the need for OGTT in 49% of patients.
  
  
  CONCLUSIONS
  This study confirms the inadequacy of FPG screening for NODAT in the first 6 weeks after transplantation, at which time 4 p.m. CapBG also outperformed OGTT. From 3 months, HbA1c had similar sensitivity to OGTT and represents a convenient alternative.
authors.affiliation: 1 Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia. 2 Department of Diabetes and Endocrinology, Royal Melbourne Hospital, Parkville, Victoria, Australia. 3 Department of Renal Medicine, Royal Melbourne Hospital, Parkville, Victoria, Australia. 4 Department of Medicine, NorthWest Academic Centre, University of Melbourne, St Albans, Victoria, Australia. 5 Address for correspondence: Dr. Christopher J. Yates, Department of Diabetes and Endocrinology, Royal Melbourne Hospital, University of Melbourne, Level 4 West, Grattan Street, Parkville, Victoria 3050, Australia.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Yates
authors.forename: Spiros
authors.initials: S
authors.lastname: Fourlanos
authors.forename: Peter G
authors.initials: PG
authors.lastname: Colman
authors.forename: Solomon J
authors.initials: SJ
authors.lastname: Cohney
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002940:Circadian Rhythm; D003430:Cross-Sectional Studies; D005215:Fasting; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use; D005951:Glucose Tolerance Test / Q000379:methods / Q000592:standards; D006442:Glycated Hemoglobin / Q000378:metabolism; D006084:Graft Rejection / Q000188:drug therapy*; D006801:Humans; D006943:Hyperglycemia / Q000139:chemically induced* / Q000175:diagnosis* / Q000378:metabolism; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D016030:Kidney Transplantation; D008297:Male; D008403:Mass Screening / Q000379:methods / Q000592:standards; D008875:Middle Aged; D009173:Mycophenolic Acid / Q000031:analogs & derivatives / Q000627:therapeutic use; D011183:Postoperative Complications / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism; D011239:Prednisolone / Q000627:therapeutic use*; D012680:Sensitivity and Specificity; D016559:Tacrolimus / Q000627:therapeutic use
chemical_list: D001786:Blood Glucose; D005938:Glucocorticoids; D006442:Glycated Hemoglobin; D007166:Immunosuppressive Agents; D009173:Mycophenolic Acid; D011239:Prednisolone; D016559:Tacrolimus; C517652:hemoglobin A1c protein, human