The original publication is available at http:/www.plosone.orgBibliographyBackground: HbA1c has been the gold standard for glycaemic control follow-up for decades. In 2009, a level of 6.5%
(48 mmol/mol) was proposed as diagnostic for diabetes. We test this cut-off in our community.
Methods: Participants (946) from a community-based study were screened for diabetes using either a fasting blood glucose
or oral glucose tolerance test (OFTT). The HbA1c cut-off of 6.5% was tested for each group. A receiver operator characteristic
(ROC) curve for both groups was generated to establish an optimal cut-off.
Results: Our study included 224 (23.7%) males and 722 (76.3%) females. Using fasting blood glucose alone, 117 (14%) were
diagnosed with diabetes 250% had an HbA1c value of $6.5% (48 mmol/mol). Using an OGTT, 147 (18%) were diagnosed
with diabetes 246% had an HbA1c value of $6.5% (48 mmol/mol). ROC curves found a level of 6.1% (43 mmol/mol) to be
optimal in both groups (AUC 0.85 and 0.82 respectively). The sensitivities were 80% and 75% and the specificities 77% and
78% respectively.  Conclusions: A cut off of 6.5% (48 mmol/mol) is a good diagnostic tool with its high specificity; however the low sensitivity limits its use. We found a level of 6.1% (43 mmol/mol) to be optimal. This emphasizes the need for evidenced based values
to be established in various population groups.National Health Laboratory Services of South AfricaUniversity Research Fund of the Cape Peninsula University of TechnologyPublishers' Versio

Erasmus, Rajiv T.

Hassan, Mogamat S.

Matsha, Tandi E.

Zemlin, Annalise E.

PLoS ONE

Stellenbosch University SUNScholar Repository

HbA1c of 6.5% to diagnose Diabetes Mellitus—Does it work for Us?—The Bellville South Africa study

BackgroundHbA1c has been the gold standard for glycaemic control follow-up for decades. In 2009, a level of 6.5% (48 mmol/mol) was proposed as diagnostic for diabetes. We test this cut-off in our community.MethodsParticipants (946) from a community-based study were screened for diabetes using either a fasting blood glucose or oral glucose tolerance test (OFTT). The HbA1c cut-off of 6.5% was tested for each group. A receiver operator characteristic (ROC) curve for both groups was generated to establish an optimal cut-off.ResultsOur study included 224 (23.7%) males and 722 (76.3%) females. Using fasting blood glucose alone, 117 (14%) were diagnosed with diabetes--50% had an HbA1c value of ≥6.5% (48 mmol/mol). Using an OGTT, 147 (18%) were diagnosed with diabetes--46% had an HbA1c value of ≥6.5% (48 mmol/mol). ROC curves found a level of 6.1% (43 mmol/mol) to be optimal in both groups (AUC 0.85 and 0.82 respectively). The sensitivities were 80% and 75% and the specificities 77% and 78% respectively.ConclusionsA cut off of 6.5% (48 mmol/mol) is a good diagnostic tool with its high specificity; however the low sensitivity limits its use. We found a level of 6.1% (43 mmol/mol) to be optimal. This emphasizes the need for evidenced based values to be established in various population groups

Annalise E Zemlin

Tandi E Matsha

Mogamat S Hassan

Rajiv T Erasmus

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HbA1c of 6.5% to diagnose diabetes mellitus -- does it work for us? -- the Bellville South Africa study.

Diabetes is a disease fuelled by the increasing worldwide obesity epidemic with significant morbidity and mortality, and the World Health Organization (WHO) estimates that it will affect 366 million individuals worldwide by 2030 [1]. Its diagnosis was previously made either according to the WHO criteria which were updated in 2006 [2] using a fasting blood glucose sample and subsequent 75 g oral glucose tolerance test (OGTT) with blood taken for glucose determination again 2 hours after an oral glucose challenge, or according to the American Diabetes Association (ADA) criteria which were updated in 2005 [3], using only a fasting blood glucose level. Using ADA criteria only has been found to underestimate the prevalence of diabetes and misses those individuals with impaired glucose tolerance (IGT), a pre-diabetic state [4]. The disadvantage of both these diagnostic approaches is that they require the patient to fast and if need confirming, would require a second fasting sample. Glucose also has a large biological and diurnal variation and depends on recent carbohydrate intake and the OGTT is fairly invasive [5]. In 2010, the ADA updated their diagnostic criteria to include an OGTT as well [6].
On the other hand, HbA1c, which is formed by the attachment of glucose to various amino groups of haemoglobin and has been used since 1977 for the long-term (2–3 month) glycaemic control follow up of diabetes, has recently been advocated by the ADA as a diagnostic tool. In 2009, the International Expert Committee of the ADA issued a statement proposing an HbA1c value of 6.5% (48 mmol/mol) as a diagnostic level for the diagnosis of diabetes. This value was chosen, as it was found to be the value after which the incidence of retinopathy, a common complication that often is present before the actual diagnosis of diabetes is made, is increased [7]. This test would be advantageous, as it does not require a fasting sample and has much less intraindividual variation.University Research Fund of the Cape Peninsula University of Technology, South Africa and the National Health Laboratory Services South Africa (grant number 94122

Zemlin, Annalise E

Matsha, Tandi

Hassan, Mogamat Shafick

Erasmus, Rajiv T

Cape Peninsula University of Technology

HbA1c of 6.5% to diagnose diabetes mellitus – Does it work for us? – The Bellville South Africa study

HbA1c of 6.5% to diagnose Diabetes Mellitus—Does it work for Us?—The Bellville South Africa study

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Stellenbosch University SUNScholar Repository

Directory of Open Access Journals

Cape Peninsula University of Technology