The Editorial Executive Committee welcomes letters, which should be less than 250 words. Before a decision to publish is made, letters which refer to a published article may be sent to the author for a response. Any letter may be sent to an expert for comment. When letters are published, they are usually accompanied in the same issue by their responses or comments. The Committee screens out discourteous, inaccurate or libellous statements. The letters are sub-edited before publication. Authors are required to declare any conflicts of interest. The Committee's decision on publication is final.

Letter to the Editor

Editor, – In response to the informative article by Michael d’Emden on glycated haemoglobin for the diagnosis of diabetes (Aust Prescr 2014;37:98-100), I wish to comment on the discrepancies between blood glucose and HbA1c tests. While it is noted that blood glucose is minimally elevated in patients with an HbA1c of less than 6.5%, often the first derangement noted in general practice is a fasting blood glucose concentration in the diabetic range. Patients may have had this level for years before the HbA1c climbs over 6.5%.

There is increasing evidence of clinical benefit from early medical intervention in type 2 diabetes.1 I am therefore concerned that by relying on the HbA1c as a single diagnostic test there is a missed opportunity to prevent disease progression using early dietary and lifestyle education and/or metformin in patients with impaired fasting glycaemia as a result of worsening insulin resistance.

Ashraf Saleh
GP, Toowoomba, Qld

Michael D’Emden, the author of the article, comments:

The article did not state that the HbA1c should be the only test used for diagnosis of type 2 diabetes. In the concluding paragraph, it says ‘the acceptance of HbA1c testing will provide an additional tool to assist in the early diagnosis of diabetes. But it should not be the only tool.’

HbA1c is one of several biochemical tests that can be used to establish the diagnosis. They each have an important role in different clinical circumstances. The Australian Diabetes Society’s HbA1c committee clearly acknowledges the important role of blood glucose measurements for the diagnosis of diabetes, in its position statement.2

References

  1. Garvey WT, Ryan DH, Henry R, Bohannon NJ, Toplak H, Schwiers M, et al. Prevention of type 2 diabetes in subjects with prediabetes and metabolic syndrome treated with phentermine and topiramate extended- release. Diabetes Care 2014;37:912-21.
  2. d’Emden MC, Shaw JE, Colman PG, Colagiuri S, Twigg SM, Jones GR, et al. The role of HbA1c in the diagnosis of diabetes mellitus in Australia. Med J Aust 2012;197:220-1.