The potential harms of statins have been exaggerated and their benefits underestimated, a new review has found.
Statins have taken a beating in the media recently: in Australia, a Catalyst two-part piece which was subsequently retracted, and in the UK, reports following a 2013 BMJ article questioned the efficacy and side effect profile of the drug class.
Now, a major review published in The Lancet shows that the benefits of statin therapy have been underestimated, and the harms exaggerated, because of a failure to acknowledge properly both the wealth of evidence from randomised trials and the limitations of other types of studies.
The review published today explains how the available evidence on the efficacy and safety of statin therapy should be interpreted, and concludes that lowering cholesterol by 2 mmol/L with an effective low-cost statin therapy (e.g. atorvastatin 40 mg daily, which costs about £2 per month in the UK) for five years in 10,000 patients would:
- Prevent major cardiovascular events (heart attacks, ischaemic strokes and coronary artery bypasses) in 1000 people with pre-existing vascular disease (“secondary prevention”), and in 500 people who are at increased risk (eg, due to their age or having hypertension or diabetes) but have not yet had a vascular event (“primary prevention”); and
- Cause five cases of myopathy (one of which might progress to the more severe condition of rhabdomyolysis, if the statin is not stopped), 5-10 haemorrhagic strokes, 50-100 new cases of diabetes and up to 50-100 cases of symptomatic adverse events (such as muscle pain).
The authors note that although further research may identify small additional beneficial or adverse effects, this is unlikely to materially alter the balance of benefits and harms for patients because of the evidence generated so far.
“Our review shows that the numbers of people who avoid heart attacks and strokes by taking statin therapy are very much larger than the numbers who have side-effects with it,” says says review author Professor Rory Collins, Clinical Trial Service Unit (CTSU), University of Oxford, UK.
“In addition, whereas most of the side-effects can be reversed with no residual effects by stopping the statin, the effects of a heart attack or stroke not being prevented are irreversible and can be devastating.
“Consequently there is a serious cost to public health from making misleading claims about high side-effect rates that inappropriately dissuade people from taking statin therapy despite the proven benefits.”
Associate Professor David Sullivan is from the Department of Chemical Pathology, Royal Prince Alfred Hospital, and the Central Clinical School, University of Sydney, described the review as “wonderful news”.
“It has the capacity to prevent the major causes of death and disability in Australia whilst providing immense savings to the cost of healthcare,” A/Prof Sullivan says.
“It does so by restoring a balanced perception of statin therapy. The review establishes that statins prevent large numbers of fatal or serious irreversible heart attacks and strokes with very little in the way of side-effects.
“Treatment, which would prevent 500 to 1000 such events per 10,000 patients, would only result in a handful of serious muscle problems, most of which would be reversible.
“The review also puts the rates of new-onset diabetes and muscle discomfort into perspective. It summarises the reassuring evidence that statin therapy carries no threat to memory, cognitive function and the risk of Alzheimer’s Disease, and reaches the conclusion that warnings concerning such possibilities should be withdrawn.”
He points out that an accompanying article by the Editor of The Lancet discusses the importance of accurate interpretation and reporting of scientific evidence and bemoans the fact that, in the UK, 200,000 patients were estimated to have stopped taking a statin in the six months after adverse media coverage.
“It will be instructive to see whether the media give this positive and reassuring message about statin therapy the prominence it deserves.”