Benefits of statin therapy

Evidence from large population studies, combined with studies in animals, genetic research and randomised controlled trials have confirmed a causal link between higher levels of LDL cholesterol in the blood and higher risks of vascular disease.


Meta-analyses of large randomised controlled trials of statin therapy indicate that each 1 mmol/L reduction in LDL cholesterol with statin therapy reduces the risk of coronary deaths and heart attacks, ischaemic strokes (strokes due to blood clots) and coronary revascularisation procedures by about 25% during each year (after the first) that treatment continues to be taken (figure 3 & 5).

The meta-analyses also indicate that larger reductions in LDL cholesterol with statin therapy produce larger reductions in the risks of these major vascular events. For example, using an effective statin regimen (such as generic atorvastatin 40 mg daily, which costs about £2 per month in the UK) to reduce LDL cholesterol by 2 mmol/L would almost halve a person's risk of a major vascular event.

It has been claimed, based on observational studies, that statin therapy might also reduce the risks of cancer and various other conditions (including respiratory diseases and infections, deep vein thrombosis, and post-operative atrial fibrillation). However, the evidence from randomised trials shows that these associations in observational studies do not reflect a causal effect of statin therapy.

Harms of statin therapy

Myopathy is a rare condition involving muscle pain, tenderness, or weakness accompanied by significant increases in blood creatine kinase concentrations. Evidence from observational studies and randomised trials points to a causal effect of statin therapy on myopathy. However, the risk of myopathy is low: about 1 extra case per 10,000 patients taking an effective statin regimen (such as atorvastatin 40 mg daily) during each year of treatment.

In addition, evidence from randomised trials has identified an increased risk of diabetes due to statin therapy: about 10-20 extra cases of diabetes developing per 10,000 treated patients per year. This excess of diabetes occurs mainly in people who are already at increased risk of developing diabetes, and its clinical significance is uncertain. In particular, although diabetes is associated with increased risk of vascular disease, statin therapy produces substantial reductions in vascular disease.

Some observational studies have suggested statin therapy may be associated with an increased risk of haemorrhagic stroke. And randomised trials indicate that statin therapy may increase the risk of haemorrhagic stroke by about one-fifth. Typically, in Western populations, this would correspond to an increase of about 5-10 extra cases per 10,000 treated patients per year. In most circumstances, the reductions in ischaemic strokes produced by statin therapy are much bigger than the increases in haemorrhagic strokes, so the risk of stroke of any kind is reduced substantially.

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