Confirming glycemic status in the Diabetes Prevention Program: implications for diagnosing diabetes in high risk adults

J Diabetes Complications. Mar-Apr 2013;27(2):150-7. doi: 10.1016/j.jdiacomp.2012.09.012. Epub 2012 Nov 7.


Aims: To examine the ability of fasting plasma glucose (FPG) and/or 2-h glucose to confirm diabetes and to determine the proportion of participants with HbA1c ≥6.5%.

Methods: Diabetes confirmation rates were calculated after a single elevated FPG and/or 2-h glucose on an oral glucose tolerance test (OGTT) using a confirmatory OGTT performed within 6 weeks.

Results: 772 (24%) participants had elevated FPG or 2-h glucose on an OGTT that triggered a confirmation visit. There were 101 triggers on FPG alone, 574 on 2-h glucose alone, and 97 on both. Only 47% of participants who triggered had confirmed diabetes. While the confirmation rate for FPG was higher than that for 2-h glucose, the larger number of 2-h glucose triggers resulted in 87% of confirmed cases triggering on 2-h glucose. Confirmation rates increased to 75% among persons with FPG ≥126 mg/dl and HbA1c ≥6.5%.

Conclusions: Only half of the persons with elevated FPG and IGT were subsequently confirmed to have diabetes. At current diagnostic levels, more persons trigger on 2-h glucose than on FPG, but fewer of these persons have their diagnoses confirmed. In individuals with FPG ≥126 mg/dl and HbA1c ≥6.5%, the confirmation rate was increased.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Aged
  • Blood Glucose / analysis*
  • Cohort Studies
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / diagnosis*
  • Diabetes Mellitus, Type 2 / epidemiology
  • Diabetes Mellitus, Type 2 / prevention & control
  • Fasting / blood
  • Female
  • Glucose Tolerance Test
  • Glycated Hemoglobin A / analysis*
  • Humans
  • Hyperglycemia / etiology*
  • Hyperglycemia / prevention & control
  • Male
  • Mass Screening
  • Middle Aged
  • Practice Guidelines as Topic*
  • Predictive Value of Tests
  • Risk


  • Blood Glucose
  • Glycated Hemoglobin A
  • hemoglobin A1c protein, human