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BMJ No 7122 Volume 315 Letters Saturday 13 December 1997
Use of statinsSee Editorial by Muldoon p 1554Evidence on effectiveness is stronger for statins than for other treatmentsEditorFreemantle et al identify the main problem with implementing the new evidence for statins-that it will entail treating many people with relatively expensive drugs.(1) They are wrong, however, to attack the Standing Medical Advisory Committee's guidance and the evidence that underpins it. The body of evidence on effectiveness, individual benefit (number needed to treat),(2) cost effectiveness,(3) methods of targeting treatment,(2)(4) and the population and cost implications of treatment policies(2,3) is arguably stronger for statins than for any treatment in wide use. The benefit from treatment (a one third reduction in major coronary events) could hardly be clearer. The reduction in relative risk is constant above a low density lipoprotein cholesterol concentration of 3.2 mmol/l. Absolute benefit is therefore determined by absolute risk, and the assumptions underpinning primary prevention are sound. Freemantle et al seriously understate benefit by citing the number needed to treat to avoid one death, which was not the principal end point in the trials. The number needed to treat to avoid major coronary heart disease events (coronary death, non-fatal myocardial infarction) is much smaller. The number needed to treat for five years at a risk of a coronary heart disease event of 3% per year is 20 for major coronary heart disease events,(2) not the 55 cited, even when benefits such as significant reductions in stroke and bypass grafts are excluded. The cost effectiveness of statin treatment at different levels of risk has been examined; at a risk of 3% per year it is comparable to or better than that for many treatments in common use.(3) The authors question the validity of the Framingham risk function and Sheffield tables for predicting risk of coronary heart disease. However, the Framingham risk function predicted average risk accurately in the placebo group in WOSCOPS (west of Scotland coronary prevention study) and gives risk estimates in individuals that agree with those derived from northern European populations.(5) The authors consider that implementation of the Standing Medical Advisory Committee's guidance is 'probably unachievable.' Are we really to accept that the health service of a civilised society cannot deliver treatment that is so effective and acceptably cost effective? The phrase 'enthusiasts for cholesterol lowering drugs' is out of place: healthcare professionals who are not enthused by the evidence from the statin trials should consider some other career. General practitioners are not overwhelmed and doing little. Many are impressed by the quality of the evidence and already implementing it. The guidance provides them with logical priorities when doing so. E J Wallis
Research assistant
M Pickin
MRC research fellow in public
health medicine
I U Haq
Specialist registrar
References
1 Freemantle N, Barbour R, Johnson R, Marchment M, Kennedy A.
The use of statins: a case of misleading priorities? BMJ
1997;315:826-8. (4 October.)
2 Haq I U, Ramsay L E, Pickin D M, Yeo W W, Jackson P R, Payne J N.
Lipid-lowering for prevention of coronary heart disease: what policy
now? Clin Sci 1996;91:399-413.
3 Working Group on Acute Purchasing. Statin therapy/HMG coA
reductase inhibitor treatment in the prevention of coronary heart
disease. Sheffield: Trent Institute for Health Services
Research, University of Sheffield, 1996. (Guidance note for purchasers
96/04.)
4 Ramsay L E, Haq I U, Jackson P R, Yeo W W, Pickin D M, Payne J N.
Targeting lipid-lowering drug therapy for primary prevention of
coronary disease: an updated Sheffield table. Lancet
1996;348:387-8.
5 Haq I U, Yeo W W, Jackson P R, Ramsay L E. A comparison of methods
for predicting coronary risk in men free of vascular disease.
Heart 1997;77(suppl 1):10.
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