Massive study finds most statin side effects aren’t caused by the drugs

To better understand the true risks, researchers analyzed data from 23 major randomized studies conducted by the Cholesterol Treatment Trialists' Collaboration. This included 123,940 participants in 19 trials comparing statins with a placebo (or dummy tablet), along with 30,724 participants in four trials that compared higher intensity statin therapy with less intensive treatment.

When the researchers reviewed reports of side effects, they found that people taking statins reported nearly the same rates of most symptoms as those taking a placebo. For instance, yearly reports of cognitive or memory problems were 0.2% among statin users and 0.2% among those on placebo. In other words, while some people may experience these symptoms during treatment, the evidence does not show that statins are the cause.

Most Listed Statin Side Effects Not Supported by Trial Data

Across nearly all the conditions listed in medication leaflets as potential side effects, there was no statistically significant increase in risk linked to statins. The analysis found no meaningful excess of memory loss or dementia, depression, sleep problems, erectile dysfunction, weight gain, nausea, fatigue, headache, or many other commonly cited concerns.

There was a small rise of about 0.1% in abnormal liver blood test results among people taking statins. However, this did not translate into higher rates of serious liver conditions such as hepatitis or liver failure. This suggests that these mild blood test changes typically do not lead to more severe liver disease.*

Christina Reith, Associate Professor at Oxford Population Health and lead author of the study, said "Statins are life-saving drugs used by hundreds of millions of people over the past 30 years. However, concerns about the safety of statins have deterred many people who are at risk of severe disability or death from a heart attack or stroke. Our study provides reassurance that, for most people, the risk of side effects is greatly outweighed by the benefits of statins."

Muscle Symptoms and Blood Sugar Findings

Earlier research from the same team showed that most muscle symptoms reported by patients are not caused by statins. Only about 1% of people experienced muscle symptoms attributable to statin therapy during the first year of use, with no additional excess risk after that. The researchers have also found that statins can slightly raise blood sugar levels, meaning that individuals already at high risk for diabetes may develop the condition somewhat sooner.

Professor Bryan Williams, Chief Scientific and Medical Officer at the British Heart Foundation, said "These findings are hugely important and provide authoritative, evidence-based reassurance for patients. Statins are lifesaving drugs, which have been proven to protect against heart attacks and strokes. Among the large number of patients assessed in this well-conducted analysis, only four side effects out of 66 were found to have any association with taking statins, and only in a very small proportion of patients.

"This evidence is a much-needed counter to the misinformation around statins and should help prevent unnecessary deaths from cardiovascular disease. Recognizing which side effects might genuinely be associated with statins is also important as it will help doctors make decisions about when to use alternative treatments."

Rethinking Statin Warning Labels

Professor Sir Rory Collins, Emeritus Professor of Medicine and Epidemiology at Oxford Population Health and senior author of the paper said "Statin product labels list certain adverse health outcomes as potential treatment-related effects based mainly on information from non-randomised studies which may be subject to bias. We brought together all of the information from large randomised trials to assess the evidence reliably. Now that we know that statins do not cause the majority of side effects listed in package leaflets, statin information requires rapid revision to help patients and doctors make better-informed health decisions."

How the Statin Safety Study Was Conducted

All of the trials included in the analysis were large-scale studies with at least 1,000 participants and followed patients for a median of nearly five years. The studies were double-blind, meaning neither participants nor researchers knew who received statins or who received the comparison treatment, reducing the risk of bias. The list of possible side effects examined in the analysis was based on those reported for the five most commonly prescribed statins.

The work was carried out by the Cholesterol Treatment Trialists' (CTT) Collaboration, coordinated by the Clinical Trial Service Unit & Epidemiological Studies Unit at Oxford Population Health and the National Health and Medical Research Council Clinical Trials Centre at the University of Sydney, Australia, representing academic researchers involved in major statin trials worldwide.

Funding was provided by the British Heart Foundation, UKRI Medical Research Council, and the Australian National Health and Medical Research Council. An Independent Oversight Panel monitors the work of the CTT.

Notes

*There were also very small increases in risk (less than 0.1%) for medical issues that involved changes in urine, and oedema (a build-up of fluid in the body typically causing swelling in the ankles, feet and legs) in the trials of statin versus placebo, but analysis of the four trials of more intensive versus less intensive statin therapy showed no significant excess risk for these changes, suggesting these excesses were not real.