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Rapid response to:


Predicting cardiovascular risk in England and Wales: prospective derivation and validation of QRISK2

BMJ 2008; 336 doi: (Published 26 June 2008) Cite this as: BMJ 2008;336:1475

Rapid Response:

Can cardiovascular risk factors be predicted accurately if blood rheology changes are ignored ?

As there is published evidence that at least five of the sixteen postulated risk factors have altered blood rheology, how can an accurate prediction be expected if such information is disregarded ?

A 1998 review from the National Institute on Aging in the USA reported that during the aging process there are rises in fibrinogen levels, blood viscosity, plasma viscosity and red cell rigidity. In 2003 we reported that the blood of halthy subjects aged between 60 and 96 years had changed shape populations of red cells. Smoking has been shown to increase blood viscosity and to reduce red cell deformability. Since 1930 there have been several reports which show that there is a direct relationship between blood viscosity and blood pressure.

The first sentence in one of Leopold Dintenfass's books on blood rheology states, "Life depends on the flow of blood." It seems totally irrational to consider cardiovascular disorders without appropriate consideration of the effects of changes in the flow properties of the blood.

Competing interests: None declared

Competing interests: No competing interests

01 July 2008
Leslie O Simpson
retired medical research worker
Dunedin, New Zealand 9077