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Pre-diabetes increases stroke risk ‘by a quarter’



Patients with pre-diabetes have around a 25% increased risk of stroke, independent of other cardiovascular risk factors, concludes a large meta-analysis.

Previous studies have suggested an overall association between pre-diabetes and future stroke but confounding factors – such as obesity and hypertension – have made estimates of the size of the association impossible.

This meta-analysis examined data from 15 studies – involving more than 700?000 patients – and divided them into three groups.

In the group of trials that defined prediabetes as NICE does – a fasting blood glucose between 6.1 and 6.9 mmol/l – there was a 21% increase risk of stroke after adjusting for CVD risk factors, compared to people with normal blood glucose. 

Trials where patients had a level of impaired glucose tolerance or impaired fasting glucose that was undefined, the risk was greatest, with an increase of 26%.

But there was no increase in CVD risk in trials defining pre-diabetes as a fasting blood glucose of between 5.6 and 6.9mmol/l, the definition currently used by the American Diabetes Association.

Study leader Professor Bruce Ovbiagele, director of the stroke programme at the University of California medical centre, said: ‘An immediate implication of our finding is that people with pre-diabetes should be aware they are at an increase risk of stroke.’

BMJ 2012; 344: e3564