Side effect myths may have put people off taking the vital medication (Image: Getty)
For decades, millions of Britons have been left confused about the side effects of statins, leading some to avoid taking the cholesterol-busting drugs entirely. The 2p daily pills, which slash risk of heart attacks and strokes, have been blamed for dozens of adverse effects, including memory loss, weight gain, depression and erectile dysfunction. However, Oxford University researchers found they were associated with only four of 66 suggested side effects, plus two others already known.
Published in The Lancet, their landmark review included data from 23 large-scale studies involving more than 150,000 patients. It found that there were similar numbers of side-effect reports across almost all conditions listed, whether or not people were taking statins. Experts called for an end to “ongoing confusion and concern about side effects”. Here’s a list of the only side effects that were linked to the drugs:
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1. Muscle symptoms
Previous research by the same team at Oxford Population Health found statins could marginally increase the risk of muscle pain or weakness. However, they were not the cause of muscle pain in more than 90% of those who experienced symptoms.
Muscle pain was found to be common in adults, regardless of whether they were taking the pills. Those cases due to statins occurred mainly during the first year of treatment.
Low or moderate intensity statin treatment was found to increase risk by around 3% and higher intensity by 8%. For every 1000 people taking a moderate intensity statin, the treatment would cause 11 (generally mild) episodes of muscle pain or weakness.
The researchers stressed that the slightly increased risk of muscle symptoms was greatly outweighed by the benefits of statins in preventing cardiovascular disease, including heart attacks and strokes.
2. Diabetes
Statins are known to slightly increase the risk of a new diabetes diagnosis; however, the majority of such cases affect people who were already close to the threshold.
This means they already had high blood sugar levels before starting the treatment.
3. Abnormal liver enzymes
Statins work by blocking an enzyme in the liver that produces cholesterol. In a small proportion of cases, the treatment was found to cause an increase in abnormal levels of liver enzymes called transaminases, which help the liver process proteins.
The Oxford study found the excess risk was linked to the intensity of statin therapy, particularly affecting patients on the highest dose (80mg per day of atorvastatin).
However, the researchers found no increased risk of serious liver problems such as jaundice or liver failure.
4. Liver function test abnormalities
The analysis also found a small increased risk of spikes in liver function tests, including other enzymes such as alkaline phosphatase.
This relationship was also dose-dependent, meaning the higher the dose, the more likely your liver is to react.
Again, this did not appear to increase the risk of serious liver problems. The researchers wrote in The Lancet: “Clarifying the clinical implications of any changes in liver function tests while taking statin therapy would be of value.”
5. Changes to urinary composition*
Urinary analysis found that statins may cause a small increase in the risk of changes in urinary composition. This essentially meant there was a marginal increase in the levels of proteins found in some patients’ urine.
Such changes can sometimes indicate kidney damage; however, the study showed no evidence of kidney injury. The changes may instead be due to a temporary change in how the kidney processes small proteins, caused by the statins.
6. Oedema*
Statins were linked to a slightly increased risk of oedema, a build-up of fluid in the body, typically causing swelling in the ankles, feet and legs.
Oedema can also be caused by standing or sitting in the same position for too long, eating too much salty food, being overweight or being pregnant.
*Researchers said the increased risks for urinary composition changes and oedema were only seen in trials comparing patients on statins to those taking a placebo, not when comparing more intensive and less intensive statin therapy. They therefore noted only the “possibility of a causal effect of statin therapy”, rather than a definite link, and described the findings as “of uncertain clinical importance”.
What about other symptoms?
The crucial study found no evidence that statins cause dozens of other undesirable effects currently listed on packaging information and in online advice.
They called for action to ensure patients and doctors are aware of the findings and can make more informed treatment decisions.
Professor Bryan Williams, chief scientific and medical officer at the British Heart Foundation, said: “Nobody is disputing the fact that patients get adverse effects throughout their life. The big question is, ‘Are they related to the drug they are taking?’ The answer here is, in large part, ‘No’.
“Many of those other things that trouble patients…have nothing to do with the treatment with statins. That is a very powerful message both for the public and for patients, and hopefully will lead to perhaps the six, seven, eight million people who should be on statins reappraising their thoughts about them.”