The potential impact and optimal cut-points of using glycated haemoglobin, HbA1c, to detect people with impaired glucose regulation in a UK multi-ethnic cohort

Diabetes Res Clin Pract. 2010 Oct;90(1):100-8. doi: 10.1016/j.diabres.2010.06.008. Epub 2010 Jul 14.


Introduction: Recommended diagnostic cut-points to detect impaired glucose regulation (IGR, also termed prediabetes: impaired fasting glucose and/or impaired glucose tolerance based on WHO 1999 criteria) are HbA1c 6.0-6.4% and 5.7-6.4% from an International Expert Committee and American Diabetes Association, respectively. We investigated the impact on prevalence/phenotype from using these criteria compared to IGR detected on oral glucose tolerance testing (OGTT) and determined optimal HbA1c cut-points for IGR in a multi-ethnic cohort.

Methods: Analysis of 8696 participants in the LEADER study of primary care individuals aged 40-75 years without diabetes, in Leicestershire (UK) who underwent OGTT and had HbA1c measured.

Results: Use of OGTT detected less people with IGR (n=1407, 16.2%) compared to HbA1c 6.0-6.4% (n=1610, 18.5%) and HbA1c 5.7-6.4%(n=3904, 44.9%), a 1.1- and 2.8-fold increase in prevalence, respectively. There were 930 (10.7%) and 534 (6.1%) people with IGR on OGTT not detected using HbA1c 6.0-6.4% and 5.7-6.4%, respectively. From ROC curve analysis, the optimal cut-point for detecting IGR in white Europeans was HbA1c>or=5.8%, sensitivity/specificity 61.5%/67.9%, but in south Asians HbA1c>or=6.0%, sensitivity/specificity 63.8%/69.4%.

Conclusion: Recommended HbA1c cut-points to detect IGR significantly increase numbers detected, however introduce a change in people identified. Using HbA1c 6.0-6.4% lacks sensitivity in white Europeans, but is a reasonable option in south Asians.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Asian Continental Ancestry Group
  • Blood Glucose / analysis
  • Cohort Studies
  • European Continental Ancestry Group
  • Female
  • Glucose Intolerance / blood*
  • Glucose Intolerance / diagnosis*
  • Glucose Intolerance / epidemiology
  • Glucose Intolerance / ethnology
  • Glucose Tolerance Test
  • Glycated Hemoglobin A / analysis*
  • Humans
  • Male
  • Mass Screening
  • Middle Aged
  • Phenotype
  • Practice Guidelines as Topic
  • Prediabetic State / blood*
  • Prediabetic State / diagnosis*
  • Prediabetic State / epidemiology
  • Prediabetic State / ethnology
  • Sensitivity and Specificity
  • United Kingdom / epidemiology


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