Diabetes work to soar under HbA1c switch

24 Feb 10

The American diabetes Association formally switched to diagnosis of type 2 diabetes by HbA1c testing in January, after an international consensus statement last year recommended it is used instead of the oral glucose tolerance test.

The European Association for the Study of Diabetes is now formally considering the move with a decision likely within a year, a leading GP diabetes expert told Pulse. But new UK research suggests the switch, under which diabetes would be diagnosed in patients with an HbA1c of 6.5% or higher, could greatly increase GP workload.

A study to be presented at the Diabetes UK conference in Liverpool next month compared prevalence of type 2 diabetes as diagnosed by either glucose tolerance testing or HbA1c in 9,500 patients from 2002 to 2009.

The oral glucose tolerance test identified 344, or 3.6%, of the cohort with diabetes. Of these 103 (1.1%), had an HbA1C of less than 6.5% and would not have been classified as having the condition using the new criteria. But when using HbA1C as the diagnostic tool, 591 – or 6.2% – of individuals were detected with diabetes.

South Asian patients were disproportionately diagnosed under the new criteria, with a 2.1-fold increase in detection, compared with a 1.4-fold rise in white Europeans.

Study leader Professor Kamlesh Khunti, professor of primary care diabetes at the University of Leicester and a GP in the city, said: ‘This is being discussed globally and a decision seems imminent.’

Dr Martin Hadley-Brown, chair of the Primary Care Diabetes Society and a GP in Thetford, Norfolk, said: ‘It’s confusing a lot of people. We will need clear guidance when it happens because it’s going to be scary.

‘Some people will be found to have a raised HbA1c that would not have been caught up on conventional testing and some people will be normal that will fail an OGTT.’