Liver dysfunction, acute renal failure, myopathy and cataract are all more common among people taking statins, research shows. But the British Heart Foundation says that the study, published on bmj.com, simply confirms that statins – like all medicines – can have side effects, and the charity says that the benefits of statins outweigh the risks.
Julia Hippisley-Cox, professor of clinical epidemiology and general practice, and Carol Coupland, associate professor in medical statistics in Nottingham, investigated the associations between use of statins and risk of adverse events in general practice patients in England and Wales.
They examined the records of almost 226,000 new users of simvastatin, atorvastatin, pravastatin, rosuvastatin or fluvastatin to estimate the effects of statin type, dose and duration on outcomes*.
The researchers found an increased risk of moderate or serious liver dysfunction, acute renal failure, moderate or serious myopathy, and cataract among patients taking statins. Only for acute renal failure and liver dysfunction was there a dose-response effect.
The type of statin did not, in most cases, influence the risk of an adverse outcome, except for liver dysfunction, where risks were highest for fluvastatin.
For all adverse outcomes, the increase in risk lasted throughout treatment and was greatest during the first year. Cataract risk returned to normal most quickly, within a year for men and women; it took longer for the risk of other adverse outcomes to fall back to normal.
The results confirmed that patients taking statins had a decreased risk of oesophageal cancer. The benefit lasted up to a year after stopping treatment for women, and 1-3 years for men.
But the authors say their findings did not substantiate other previously suspected benefits of taking statins, such as a reduced risk of Parkinson’s disease, venous thromboembolism, rheumatoid arthritis, osteoporotic fracture and dementia.
They conclude: "Claims of unintended benefits of statins, except for oesophageal cancer, remain unsubstantiated, although potential adverse effects at population level were confirmed and quantified. Further studies are needed to develop utilities to individualise the risks so that patients at highest risk of adverse events can be monitored closely."
Authors of an accompanying editorial "Balancing the intended and unintended effects of statins" say the research shows that when used according to guidelines, the benefits of statins outweigh the risks.
*cardiovascular disease, moderate or serious myopathic events, moderate or serious liver dysfunction, acute renal failure, venous thromboembolism, Parkinson’s disease, dementia, rheumatoid arthritis, cataract, osteoporotic fracture, gastric cancer, oesophageal cancer, colon cancer, lung cancer, melanoma, renal cancer, breast cancer, or prostate cancer.