The Lancet study, intended to help patients and clinicians make informed decisions on use of statins, highlights 'large-scale evidence' from randomised trials that statins lower the risk of major vascular events by around a quarter for each 1 mmol/L reduction in LDL cholesterol for each year after the first 12 months in which the drugs are taken.
The review says: 'Statin therapy has been shown to reduce vascular disease risk during each year it continues to be taken, so larger absolute benefits would accrue with more prolonged therapy, and these benefits persist long term.
'The only serious adverse events that have been shown to be caused by long-term statin therapy—ie, adverse effects of the statin—are myopathy (defined as muscle pain or weakness combined with large increases in blood concentrations of creatine kinase), new-onset diabetes mellitus, and, probably, haemorrhagic stroke.'
Treatment of 10,000 patients for five years with a regimen such as atorvastatin 40mg daily is likely to cause 'about 5 cases of myopathy (one of which might progress, if the statin therapy is not stopped, to the more severe condition of rhabdomyolysis), 50-100 new cases of diabetes, and 5-10 haemorrhagic strokes', the authors add.
The review expresses concern that exaggerated or inaccurate claims about side effects associated with statins could put patients off using them, leaving them at risk of heart attacks or strokes that could have been prevented.
'Placebo-controlled randomised trials have shown definitively that almost all of the symptomatic adverse events that are attributed to statin therapy in routine practice are not actually caused by it (ie, they represent misattribution),' the review says. 'The large-scale evidence available from randomised trials also indicates that it is unlikely that large absolute excesses in other serious adverse events still await discovery.'
RCGP chair Dr Maureen Baker said: 'This study cuts through a lot of the controversy surrounding statins.
'GPs are highly trained to prescribe based on the individual circumstances of the patient in front of them. A decision to prescribe statins will never be taken lightly and should always be the result of a discussion between GP and patient. It remains essential that patients who are prescribed statins undertake regular medication reviews.
'We hope this research reassures patients who are on statins that in the majority of cases statins are safe and effective drugs – but in most cases where adverse side effects are seen, these are reversible by stopping taking statins.'