Cholesterol lowering with statins is of known benefit for people at increased risk of heart attack. However, current treatment guidelines do not recommend that doctors take account of a person's risk of stroke when deciding whether to use statin therapy. Rory Collins from the Clinical Trial Service Unit, Oxford, UK, and colleagues report detailed results from a five-year study of the effect of simvastatin or placebo among 20,536 people with either a history of stroke or other cerebrovascular disease (3280 people) or at high risk of stroke for other reasons (17,256 people).
Participants were randomly assigned 40 mg simvastatin daily or matching placebo for five years, which yielded an average reduction in LDL cholesterol of 1 mmol/litre. There was a very definite 25% proportional reduction in the incidence of stroke among patients in the simvastatin group (444 strokes; 4.3%) compared with those in the placebo group (585 strokes; 5.7%). This reflected a 30% proportional reduction in the incidence of 'ischaemic' strokes (ie, due to artery blockage in the brain), with no apparent difference in the incidence of 'haemorrhagic' strokes (ie, due to bleeding into the brain). Although the stroke rate was not significantly reduced by simvastatin among participants with a history of cerebrovascular disease, there was a substantial reduction in the combined risk of all major vascular events (ie, heart attacks, strokes, and revascularisation procedures) among these patients.
Rory Collins comments: "This study shows that statin therapy rapidly reduces the incidence not only of heart attacks but also of ischaemic strokes, with no adverse effect on haemorrhagic strokes, even among individuals who do not have high cholesterol concentrations. Allocation to 40 mg simvastatin daily reduced the rate of ischaemic strokes by about one-quarter and so, after making allowance for non-compliance in this study, actual use of this regimen would probably reduce the stroke rate by about a third. The study also provides definitive evidence that statin therapy is beneficial for people with a history of stroke or other cerebrovascular disease. National and international treatment guidelines should now be revised so that stroke risk reductions are taken into account when the initiation of statin therapy is being considered."
Contact: Professor Rory Collins, Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Harkness Building, Radcliffe Infirmary, Oxford OX2 6HE, UK; T) 44-0-1865-404834; F) 44-0-1865-558817; E) secretary@ctsu.ox.ac.uk
Journal
The Lancet