June 1, 2015

HbA1c Test May Not Be Applicable in Some Cases

This article shows why the American Diabetes Organization may be in the minority and not in the forefront of diabetes diagnosis. It raises some valid concerns and reasons not to rely on the gold standard American doctors are relying on for diagnosing type 2 diabetes.

New research published in Diabetologia (the journal of the European Association for the Study of Diabetes) highlights how anemia--a common condition in the general population, especially in women--can lead to a false diagnosis of diabetes based on HbA1c, when a person's blood sugar control is actually normal. The research is by Dr Emma English, University of Nottingham, UK, and colleagues.

In recent years, the World Health Organization (WHO) and the American Diabetes Association (ADA) have both pushed and advocated the use of the HbA1c for diagnosing type 2 diabetes. Following the recommendations of the WHO to use HbA1c as the diagnostic method for type 2 diabetes, the United Kingdom (UK) has issued expert guidance that one of the major issues affecting this usage was anemia.

With approximately 29% of non-pregnant women worldwide having anemia (the latest estimate from 2011), this translates to a significant number of people where the use of HbA1c for diagnosis of diabetes is unsuitable. The latest WHO estimate for anemia prevalence in men was 13%, likely to be higher in elderly men, although data are scarce.

I have several other blogs about the ineffectiveness of the HbA1c for diagnosis. That being said, generally, the HbA1c is effective for white Anglo-Saxon adults with the following exceptions:
  1. The HbA1c should never be considered for anyone undergoing dialysis – read my blog here.
  2. The HbA1c cannot be used for people with iron-deficiency anemia.
  3. The HbA1c has been shown by this study that it is unreliable for diagnosis of diabetes in children – see my blog here.

There is also much doubt about many other ethnicities not relying on the HbA1c as some significant variances have been proven. Some in the medical profession are openly stating that the A1C test needs to be standardized for each ethnic group

The review of research between 1990 and 2014 included studies which had at least one measurement of HbA1c and glucose, and at least one index of anemia involving non-pregnant adults not diagnosed with diabetes. The authors identified 12 studies suitable for inclusion, the majority of which focused on iron deficiency anemia and, in general, demonstrated that the presence of iron deficiency with or without anemia led to an increase in HbA1c values compared with controls, with no corresponding rise in blood glucose, thus rendering any diagnosis of diabetes in such individuals unreliable without further tests.

Calling for more research in view of the relatively small number of studies they were able to include in their review, the authors conclude: "The key questions that are still to be answered are whether anemia and red blood cell abnormalities will have a significant impact on the diagnosis of diabetes using HbA1c in the general population--something that is now widely performed."”

Until the ADA realizes these deficiencies in the HbA1c, some people will be diagnosed with type 2 diabetes that do not have diabetes. Others will not be diagnosed when in fact they may have type 2 diabetes. The ADA belief that one-size-fits-all approach to diabetes may someday be a liability that the ADA can no longer afford.

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