no good evidence for statins in primary prevention
Hingorani and Hemingway are advocating that we put millions more
healthy people on long term statin therapy in an attempt to prevent some
people from dying of heart disease. This approach is analogous to locking
up all young men in order to reduce the crime figures. It might have some
merit were there any good evidence that statins prevent healthy people
from dying prematurely: but there is not.
One problem is that very few trials have been about pure primary
prevention. This is because the effects are so small in healthy
populations that the researchers have had to include some unhealthy ones
to ensure that enough people die during the trial period. The oft-quoted
WOSCOPS(1) study included subjects with stable angina and intermittent
claudication. Despite enrolling over six thousand subjects and following
them up for 5 years it failed to show a significant effect on all cause
mortality.(Don't be seduced by figures on cardiovascular mortality. There
is not point in being spared a fatal heart attack only to be killed in
some other way by the treatment. )
By pooling results from many trials, metanalyses attempt to show
effects where individual trials have failed. The recent Cochrane review(2)
highlighted some of the limitations of existing trial evidence. The
authors complained about "selective reporting of outcomes, failure to
report adverse effects and inclusion of people with cardiovascular
disease". They included in their analysis trials where up to 10% of the
participants had pre-existing cardiovascular disease. Even then the effect
on mortality was minimal: one death prevented every 588 person years. (31%
of the weight of this metanalysis comes from the WOSCOPs trial.)
Another problem with the trials is bias. Many trials are not properly
blinded. For example clinicians treating subjects will usually know their
lipid parameters, and easily guess whether they receiving active treatment
or placebo. Therapeutics Initiative(3) found that, when trials subject to
bias were removed from the equation, the effect on mortality disappeared.
They concluded that "statins do not have a proven net health benefit in
primary prevention populations and do not represent a good use of scarce
There are enough previously well people already hopelessly
medicalised by statin treatment, subjected to the cost and anxiety of
frequent visits to the doctor, regular blood tests, and collection of
repeat prescriptions, not to mention the many who endure muscle aches and
pains, not realising it is due to their tablets. And all because their GP
has thoughtlessly put them on statins in the misguided belief that their
cholesterol level was "too high" Let us not make the situation worse by
lowering the threshold for treatment.
1)Shepherd J et al. Prevention of coronary heart disease with
pravastatin in men with hypercholesterolemia. West of Scotland Coronary
Prevention Study Group.
N Engl J Med 1995 Nov 16;333(20):1301-7.
2)Taylor F, Ward K, Moore TH, Burke M, Davey Smith G, Casas JP,
Statins for the primary prevention of cardiovascular disease (Review)
Cochrane Database Syst Rev. 2011 Jan 19;1:CD004816.
3)Therapeutics Initiative. University of British Columbia. Do statins
have a role inprimary prevention: an update. Therapeutics letter 77.
Competing interests: No competing interests