Preventive strategies that use statins to ward off the risk of cardiovascular disease need to bear in mind the drugs’ potential to increase the risk of cataracts, liver dysfunction, myopathy and acute renal failure, a ‘real-world’ study from researchers at the UK’s University of Nottingham suggests.

At the same time, the population-based cohort study published in the BMJ confirmed the ability of statins to reduce cardiovascular disease risk while also lowering the risk of oesophageal cancer.

No significant association was found between statin use and the risk of Parkinson’s disease, rheumatoid arthritis, venous thromboembolism, dementia, osteoporotic fractures or a number of cancers including gastric, colon, lung, renal, breast or prostate. And in an accompanying editorial, two senior cardiologists said the benefits of statins, when used according to current guidelines, outweighed their risks.

The study authors – Julia Hippisley-Cox and Carol Coupland, respectively professor of clinical epidemiology and general practice and associate professor of medical statistics in the University of Nottingham’s Division of Primary Care – looked at data on statin use from 368 general practices in England and Wales using the general practice research database, QResearch.

Clinical outcomes were examined in 2,004,692 patients aged 30-84 years who were registered with the practices between January 2002 and June 2008. Of this total, 10.7% were new users of statins, 70.7% were prescribed simvastatin (Zocor), 22.3% atorvastatin (Lipitor), 3.6% pravastatin (Pravachol). 1.9% rosuvastatin (Crestor) and 1.4% fluvastatin (Lescol).

The researchers estimated the effects of statin type, dose and duration on clinical outcomes previously associated with these drugs and then calculated the respective numbers needed to treat and harm.

They found that for every 10,000 high-risk women treated with statins, there would be around 271 fewer cases of cardiovascular disease, eight fewer cases of oesophageal cancer, 307 extra cases of cataracts, 74 more patients with liver dysfunction, 39 more patients with myopathy and 23 more with acute renal failure. The figures were similar for men, although there were higher rates of myopathy.

The pattern of adverse events did not vary significantly between the various types of statin, except in the case of liver dysfunction, where the highest risks were associated with fluvastatin.

The analysis also showed that the risks of liver dysfunction, acute renal failure and possibly myopathy with statin use were dose-related. Since “liver dysfunction is common and the other two outcomes potentially life-threatening, the findings would tend to support a policy of using lower doses of statins in people at high risk of the adverse event”, Hippisley-Cox and Coupland said.

Other than the positive association between statin use and the risk of oesophageal cancer, claims of unintended benefits with these drugs “remain unsubstantiated”, they noted.

In an accompanying editorial in the BMJ, Alawi Alsheikh-Ali, consultant cardiologist at the Institute of Cardiac Sciences in Abu Dhabi, United Arab Emirates, and Richard Karas, executive director of the Molecular Cardiology Research Institute in Boston, US, described the study findings as “reassuring”.

When statins are used in accordance with current guidelines, the risk-benefit ratio is in their favour, Alsheikh-Ali and Karas concluded.