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Letters to the Editor
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Statins
Customers will need to make informed choices
From Mr D. G. Phizackerley, MRPharmS
In his letter (PJ, 22 May, p638), Hemant
Patel argues the case for over-the-counter
simvastatin. He cites the Heart Protection Study1 as evidence of the
benefit of treating patients at low risk of coronary disease.
Unfortunately this is not the case. The rate of vascular events (ie,
the level of risk) in the group of patients in the trial who received
placebo was 25 per cent over five years, which equates to 50 per cent
risk over 10 years. The anticipated use of OTC simvastatin is in patients
who have a level of risk of between 10 and 15 per cent risk over 10 years,
so it may not be appropriate to extrapolate the benefits from this trial
to a lower risk population.
Interestingly, in the Heart Protection Study the active treatment was
40mg simvastatin daily and this produced an absolute risk reduction (ARR)
in major vascular events of 5.4 per cent and a relative risk reduction
(RRR) of 21 per cent with an NNT (number needed to treat) of 18 (ie,
18 patients needed to be treated for five years to prevent one event).
The ARR for death was 1.8 per cent (RRR = 12 per cent) and this means
that to prevent a death, 56 patients would need to be treated for five
years.
In their review of the evidence for statins for primary prevention, researchers
at the University of British Columbia have analysed the results from
five primary prevention trials.2 They conclude that 71 patients with
cardiovascular risk factors have to be treated with a statin for three
to five years to prevent one myocardial infarction or stroke. Therefore,
70 people gain no benefit from taking a statin for three to five years.
The authors also comment that their analysis showed that total mortality
was not reduced by treatment with a statin.
Based on the findings of the paper from the University of British Columbia,
and assuming that a dose of 10mg simvastatin produces the same level
of benefit as the much higher statin doses used in the primary prevention
trials, it is possible to estimate the investment required to prevent
one event. Assuming a price of £12 for 28 days, between £33,000
and £55,000 will have to be paid by customers to prevent one vascular
event (although the cost to the individual will only have been between £468
and £780). Customers will need to make a judgement on whether this
level of investment is worthwhile.
The challenge for the profession will be to explain to customers what
taking (and paying) for a statin for a long period will mean to them.
Customers will need to be involved in discussions that help them to understand
their current level of risk, the evidence supporting the use of statins,
the likely benefits in terms of absolute risk reduction and the choices
that they can make between this and other interventions (including lifestyle
changes). Baseline risk, absolute risk reduction, relative risk reduction
and numbers needed to treat are all terms that confuse some health professionals.3 Pharmacists will need to ensure that their customers understand these
issues so that they are able to make an informed choice about whether
to invest in simvastatin or membership of their local gymnasium.
David Phizackerley
Prescribing Team Manager
Western Sussex Primary Care Trust
References
1. Heart Protection Study Collaborative Group. MRC/BHF Heart protection
study of cholesterol lowering with simvastatin in 20,536 high-risk
individuals: a randomised placebo controlled trial. Lancet 2002;360:7–22.
2. Do statins have a role in primary prevention? Therapeutics Letter
48. April–June 2003.
3. Young JM, Glasziou P, Ward JE. General practitioners’ self-rating
of skills in evidence-based medicine: validation survey. BMJ 2002;324:950–1.
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