There seems to be some confusion over the role of the New Zealand tables (Q&A, November).
The tables are used to assess the absolute risk per annum of a cardiovascular event (heart attack, stroke, fatal and non-fatal) at various ages.
The data for the New Zealand tables are apparently derived from the Framingham study (Fahey, British Medical Journal, 1998; 317: 1093-4), as are the data for the Sheffield tables.
Your answer to the question posed is right, if a little impracticable. Ideally, we need to repeat the Framingham study in this country. Some chance!
Once the risk level has been assessed, a decision can be made using whichever set of guidelines you wish.
The New Zealand tables recommend a 3% risk before intervention is considered. However, since the level at which, for example, statins may be used is an arbitrary one, based as much on financial considerations as on clinical ones, this can be modified.
The New Zealand tables have many advantages: they are highly visual and easy to use, patients can easily see where their own risk is in relation to their peers, and they do not require large amounts of data to be punched in by the doctor.
They have been criticised because they require the total cholesterol/HDL level to be measured before a risk assessment can be made.
On the other hand, they can also be used to demonstrate to those younger 'worried well' with a low risk that they do not need to have it measured.
Dr K Pearce, GP, Harrow, Middlesex
CHD risk scores identify right patients to treat
I found David Archer's article on lipid scores ('Framingham risk scores help target primary prevention', November) most interesting.
He reported the real problems in finding the right patients to treat.
Dr PJ Walker, GP, Whitwell, Herts
Enhancing the practice nurse's role
The whole concept of Guidelines in Practice will be invaluable as primary care group, evidence-based practice is implemented. This will be a very helpful journal for all aspects of practice nursing, particularly enhancement of the practice nurse's role.
Sue Robinson, Practice Sister, Chelmsford, Essex