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The Utility of HbA1c as a Diagnostic Criterion of Diabetes

Hee-Jung Kim1, Eun Young Choi, Eal Whan Park

  • 1Department of Family Medicine, Dankook University College of Medicine, Cheonan, Korea.

Korean Journal of Family Medicine
|June 30, 2012
PubMed

Insights

Hemoglobin A1c (HbA1c) testing underestimated diabetes prevalence compared to 2003 ADA criteria in high-risk individuals. The optimal HbA1c diagnostic cut-off was determined to be 6.45%.

Area of Science:

  • Endocrinology
  • Clinical Diagnostics
  • Diabetes Mellitus Research

Background:

  • Hemoglobin A1c (HbA1c) is a key biomarker for diabetes diagnosis.
  • The 2003 American Diabetes Association (ADA) criteria are a standard for diabetes diagnosis.
  • Investigating the diagnostic utility of HbA1c is crucial for accurate diabetes detection.

Purpose of the Study:

  • To compare the diagnostic accuracy of HbA1c criteria with the 2003 ADA criteria for diabetes diagnosis.
  • To determine the optimal cut-off value for HbA1c in diagnosing diabetes using receiver operating characteristic (ROC) curves.
  • To assess the prevalence of newly diagnosed diabetes using both criteria in high-risk individuals.

Main Methods:

  • Study included 224 non-diabetic subjects with fasting plasma glucose > 100 mg/dL.
  • Subjects underwent a 75g oral glucose tolerance test (OGTT).
  • Diabetes diagnosis was established using the 2003 ADA criteria and HbA1c levels.

Main Results:

  • HbA1c criteria (≥6.5%) identified fewer diabetes cases (47.8%) than 2003 ADA criteria (58.2%), underestimating prevalence.
  • HbA1c at 6.5% showed 73.5% sensitivity and 89.1% specificity compared to ADA criteria.
  • The optimal HbA1c cut-off for diabetes diagnosis was 6.45% (AUC=0.85), with moderate agreement (kappa=0.60).

Conclusions:

  • HbA1c testing, at a 6.5% threshold, underestimates diabetes prevalence in high-risk individuals compared to 2003 ADA criteria.
  • An HbA1c cut-off of 6.45% provides a balance of sensitivity and specificity for diabetes diagnosis.
  • Findings suggest HbA1c is a valuable, though not perfect, tool for diabetes screening and diagnosis.
Abstract

Keywords:
DiabetesDiagnosisGlucose Tolerance TestHemoglobin A, Glycosylated

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