HbA1c of 6.5% to Diagnose Diabetes Mellitus: The Bellville South Africa Study
Author Information
Author(s): Zemlin Annalise E., Matsha Tandi E., Hassan Mogamat S., Erasmus Rajiv T.
Primary Institution: Cape Peninsula University of Technology
Hypothesis
Is an HbA1c level of 6.5% an effective diagnostic tool for diabetes in our community?
Conclusion
An HbA1c cut-off of 6.5% is a good diagnostic tool with high specificity, but its low sensitivity limits its use.
Supporting Evidence
- Using fasting blood glucose, 14% were diagnosed with diabetes, with 50% having an HbA1c value of ≥6.5%.
- Using an OGTT, 18% were diagnosed with diabetes, with 46% having an HbA1c value of ≥6.5%.
- The optimal HbA1c cut-off for diabetes diagnosis was found to be 6.1%.
Takeaway
The study tested if a blood test level of 6.5% can tell if someone has diabetes, and found that a lower level of 6.1% works better.
Methodology
Participants were screened for diabetes using fasting blood glucose or oral glucose tolerance tests, and ROC curves were generated to establish optimal cut-offs.
Limitations
The study did not assess haemoglobin and iron status, renal impairment, or various haemoglobinopathies that could affect HbA1c levels.
Participant Demographics
The study included 946 participants, with 224 males and 722 females, primarily from a Coloured (mixed ancestry) population.
Statistical Information
Confidence Interval
(52, 54)
Digital Object Identifier (DOI)
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