Patients worried about potential side effects of statins can rest easy, according to a new large-scale study: The vast majority of adverse effects listed on statin medications simply never occur.

The study, published in The Lancet, analyzed individual patient data from 154,000 patients in 23 large, randomized controlled trials conducted by the Cholesterol Treatment Trialists’ Collaboration.

Researchers compiled 66 non-muscle, non-diabetes outcomes that statin labels claim may be caused by these drugs — including cognitive problems, depression, sleep issues, kidney injury, sexual dysfunction, liver disease, and many others.

Only four of the 66 undesirable outcomes attributed to statins met false discovery rate significance criteria: abnormal liver transaminases, minor urinary composition changes (mostly mild proteinuria), edema, and other liver function test abnormalities. Absolute risks for these outcomes, however, were under 0.2% annually.

By contrast, the authors found moderate-intensity statin use for 5 years would typically prevent about 1000 major vascular events per 10,000 patients with established cardiovascular disease and about 500 events per 10,000 high-risk patients without prior events — placing the small excess risks for adverse events in a clinical context.

Lack of Causal Links

A dose-response relationship was observed for liver enzyme findings. In trials comparing more intensive with less intensive statin therapy, abnormal transaminases and other liver test abnormalities occurred more frequently with high-intensity statins. 

The dose-related effect was largely driven by atorvastatin 80 mg. When this trial was excluded, the magnitude of liver enzyme elevations was substantially reduced. Nevertheless, no increase in hepatitis, liver failure, or jaundice was found. The investigators emphasize these liver-related signals reflected biochemical laboratory abnormalities rather than clinically significant liver disease.

Importantly, the study found no causal link between statins and commonly assumed adverse effects, including:

• Cognitive impairment or memory loss
• Dementia or Alzheimer’s disease
• Depression or anxiety
• Sleep disturbance
• Peripheral neuropathy
• Acute kidney injury
• Sexual dysfunction

Investigators found no increase in acute kidney injury, hematuria, dysuria, or declines in renal function. They noted the observed urinary signal was limited primarily to mild proteinuria without evidence of clinical kidney disease or a dose-response relationship.

‘Powerful Reassurance’

Eligible trials enrolled at least 1000 participants, had a planned treatment duration of 2 years or longer, and used a double-blind design comparing statin therapy with placebo or more-intensive vs less-intensive statin regimens. Investigators controlled the false discovery rate at 5% when determining statistical significance. Median follow-up was 4-5 years.

Eugene Yang, MD, MS, professor of the Division of Cardiology at the University of Washington School of Medicine in Seattle, does not believe this study will affect how doctors prescribe statins but will perhaps make patients feel safer when taking the medication.

“For clinicians and patients who worry about rare or poorly defined side effects, this provides powerful reassurance,” Yang said. “If anything, this kind of evidence should make clinicians more confident in recommending statins and help patients feel more comfortable taking them when indicated.”

That growing confidence may also help clinicians address lingering fears among patients about how side effects might endanger health.

However, the study also points to the challenges of medication labels from the onset, notes Ana C. Iribarren, MD, an instructor at the Smidt Heart Institute at Cedars Sinai in Los Angeles.

“The study reveals a fundamental problem: Product labels are based primarily on unblinded observational data and post-marketing reports, which are highly susceptible to the nocebo effect and attribution bias,” she said. “The current disconnect between evidence and labeling creates real clinical harm.”

Understanding the Many Benefits

The authors cite prior analyses showing that exaggerated safety concerns have led to large-scale statin discontinuation, with one UK-based estimate suggesting that more than 200,000 patients may have stopped statin therapy following misleading reports — potentially resulting in thousands of avoidable cardiovascular events over the subsequent decade.

Christina Reith, PhD, associate professor at Oxford Population Health, University of Oxford, Oxford, England, and lead investigator of the study, expressed optimism that the findings could shift attitudes and labeling within the healthcare community.

“We hope this research will help people better understand that the substantial benefits of statins in preventing cardiovascular events — such as heart attacks and strokes caused by blocked blood vessels — far outweigh their risks,” she said. “Ultimately, we hope this will help both patients and clinicians make more informed decisions about statin therapy.”

The study was independently supported. Reith reported having no relevant financial relationships.

Lois Anzelowitz Levine is a medical and lifestyle writer in Dallas.