Intended for healthcare professionals

Practice Rational Testing

Using haemoglobin A1c to diagnose type 2 diabetes or to identify people at high risk of diabetes

BMJ 2014; 348 doi: (Published 25 April 2014) Cite this as: BMJ 2014;348:g2867

Re: Using haemoglobin A1c to diagnose type 2 diabetes or to identify people at high risk of diabetes

A recent study published in the BMJ Open Diabetes Research Journal highlighted the use of baseline HbA1c levels on the development of diabetes. The 2014 study set in Japan gave promising results by developing lifestyle interventions in primary care settings with implications on future management for type 2 diabetes (T2DM) and of those at risk of developing this disorder.(1)

The use of HbA1C as a method of diagnosis and prevention in diabetes care is nothing new within diabetes specialism in the UK. Much has been learned from Twin studies concerning type 1 and 2 diabetes. It was the late Professor Pyke (an eminent diabetes consultant at the internationally renowned Kings College Hospital in London) and his team that in 1979 established the profound genetic link present in T2DM. Professor Pyke was first to recognise the potential of twins participating in research. (2)(3)

Twin studies of normal glucose-tolerant individuals whose monozygotic twin had T2DM provided compelling evidence; that these persons have an 80% probability of developing T2DM and, therefore, can most likely be classified as having prediabetes. (4)

A further 1979 study found the HbA1c blood test may also be a useful predictor of those patients likely to respond to diet alone and those likely to require treatment with an oral hypoglycaemic agent. (5)

Twin studies in unaffected co-twins of diabetics (T2DM).found the HbA1c value in the twins was at or slightly above the upper limit of the normal range and there was no overlap between them and controls. The 1981 study suggested that even slight hyperglycaemia is reflected by a raised HbA1c value, and that this may therefore be a good indicator of early diabetes. (6)

HBA1c as a method of T2DM diagnosis can potentially be used to instigate preventative measures as shown by the above mentioned Japanese study.

There is much talk about the prevention of diabetes. In practice T2DM management is undermined with inadequate education, inadequate resources poor understanding of diets followed by rapid progression to polypharmacy and global medicalisation. In the UK primary care does not have the facilities to cope with the diabetes epidemic and secondary care is also in dire straits.

It is thirty-five years since HbA1c was first mooted as a measurement for T2DM for both diagnosis and prevention, isn’t it about that its potential was realised?

(1). Effect of baseline HbA1c level on the development of diabetes by lifestyle intervention in primary healthcare settings: insights from subanalysis of the Japan Diabetes Prevention Program /Naoki Sakane1, Juichi Sato2, Kazuyo Tsushita3, Satoru Tsujii4, Kazuhiko Kotani1,5,Makoto Tominaga6, Shoji Kawazu7, Yuzo Sato8, Takeshi Usui9, Isao Kamae10,Toshihide Yoshida11, Yutaka Kiyohara12, Shigeaki Sato13, Kokoro Tsuzaki1,Kaoru Takahashi1,14, Hideshi Kuzuya15,16, the Japan Diabetes Prevention Program (JDPP) Research Group. BMJ Open Diab Res Care 2014;2:e000003
(2) Pyke DA. Diabetes: the genetic connections. Diabetologia 1979;17:333-43.
(3) Barnett AH, Eff C, Leslie RDG, Pyke DA. Diabetes in identical twins.
A study of 200 pairs. Diabetologia 1981;20:87-93.
(4) Cerasi E, Luft R. Insulin response to glucose infusion hi diabetic and non-diabetic monozygotic twin pairs. Genetic control of insulin response? Acta Endocrinol (Coperth). 1967;55:330-345.
(5) D M Fraser, A F Smith, R S Gray, D Q Borsey, M E Sinclair, B F Clarke, L J P Duncan Glycosylated haemoglobin concentrations in newly diagnosed diabetics before and during treatment British Medical Journal, 1979, 1, 979-981
(6) A H Barnett, A J Spiliopoulos, D A Pyke, W A Stubbs, J Burrin, K G M M Alberti. Metabolic Studies In Unaffected Co-Twins Of Non-Insulin-Dependent Diabetics. Br Med J (Clin Res Ed) 1981;282:1656-1658

Competing interests: No competing interests

09 May 2014
Jane E Collis
Independent Researcher
No affiliation
Kenilworth Warks UK