By Christian Duffin
There is little evidence that prescribing statins for primary prevention is either cost effective or will bring improvements in patients' quality of life, according to a gold-standard systemic review by UK researchers.
They warned that although prescribing statins do reduce mortality rates, there is no evidence to support their use in patients at low cardiovascular risk.
Simvastatin 20mg is available for sale over the counter at pharmacies, but though previous research has highlighted the benefits of statins for reducing high blood cholesterol among patients with coronary artery disease, the case for primary prevention was less clear.
A team from the Cochrane review heart group at the London School of Hygiene and Tropical Medicine examined 14 randomised controlled trials of 34,000 patients given statins for a minimum of one year and follow-up of six months in adults with no restriction on their LDL or HDL-cholesterol levels, and where less than 10% of the patients enrolled in the trial had a history of CVD. Eleven of the trials involved patients with specific conditions, such as raised lipids, diabetes or hypertension.
They found a 17% reduction in all-cause mortality and a 30% reduction in a composite outcome of fatal and non-fatal cardiovascular endpoints. But they stressed that the quality of the evidence was poor.
But there was no clear evidence of any significant harm caused by statin prescription or of effects on patient quality of life, the researchers found.
The research team was led by Dr Fiona Taylor, a public health research consultant at the London School of Hygiene and Tropical Medicine. She concluded: ‘Although reductions in all-cause mortality, composite endpoints and revascularisations were found with no excess of adverse events, there was evidence of selective reporting of outcomes, failure to report adverse events and inclusion of people with cardiovascular disease.
‘Only limited evidence showed that primary prevention with statins may be cost effective and improve patient quality of life. Caution should be taken in prescribing statins for primary prevention among people at low cardiovascular risk.'
She added: ‘This current systematic review highlights the shortcomings in the published trials of statins for primary prevention. Selective reporting and inclusion of people with cardiovascular disease in many of the trials included in previous reviews of their role in primary prevention make the evidence impossible to disentangle without individual patient data.'
Dr Carl Heneghan, a GP and director of the centre for evidence-based medicine at the University of Oxford, said: ‘The results are at odds with previous reviews such as the Cholesterol Treatment Trialists' Collaboration's review, which found large reductions in major vascular endpoints in the subgroup of people without previous myocardial infarction or history of coronary heart disease.
But he added: ‘The review is helpful in highlighting that the current evidence does not support use of statins below a 1% annual all-cause mortality risk or an annual CVD event rate of below 2%. This is aligned with NICE guidance, where statins should be used as part of the management strategy for the primary prevention of CVD for adults who have a 20% or greater 10-year risk of developing CVD.'
Cochrane Database of Systematic Reviews 2011, Issue 1. Art. No.: CD004816'Little evidence' for statin use in low-risk patients