Abstract
WG John, on behalf of the UK Department of Health Advisory Committee on Diabetes. Diabetic Medicine 2012;29:1350–7
For many years guidelines recommended the measurement of blood glucose for diagnosing diabetes mellitus. Over the years evidence that glycated (glycosylated) haemoglobin (HbA1c) could be used has grown and in 2011 this was officially recognized by the World Health Organization (WHO). WHO recommend an HbA1c concentration of 48 mmol/mol (6.5%) as the cut-off point for diagnosis. It remained unclear what diagnostic approach should be adopted towards patients with HbA1c values above the reference range but below the WHO cut-off point for diabetes.
This as well as other important clinical and laboratory issues pertaining to the diagnosis of diabetes mellitus have been addressed in the above paper. It summarizes the recent recommendations of the UK expert advisory body convened by the Department of Health in order to provide guidance on the implementation the WHO recommendations for diagnosis of diabetes mellitus in UK clinical practice. Additionally the paper highlights some important differences between the new UK guidelines and the existing guidelines of the American Diabetes Association.
The UK recommendations divide patients into three groups depending on their HbA1c result (≥ 48, 42–47 and < 42 mmol/mol) and provide detailed guidelines for each group. The emphasis is on the borderline HbA1c results (42–47 mmol/mol). This report discusses the most common clinical scenarios with these patients and advises on treatment, further testing strategies and frequency of monitoring.
This paper also discusses the interpretation of HbA1c results, the limitations of HbA1c as a diagnostic test (e.g. variant haemoglobins, altered lifespan of red blood cells, age, ethnicity) and provides a comprehensive list of situations in which HbA1c cannot be used for diagnosis (e.g. in children, young people, pregnancy, acutely ill, patients with suspected type 1 diabetes or in renal failure, etc.) summarized in detailed algorithms for recommended approach. The article appears to be an invaluable tool for clinicians investigating patients with suspected diabetes as well as health-care professionals involved in the interpretation of HbA1c results.