People are more worried about severe muscular problems when taking statins than they should be: These side effects are exceedingly rare, research published Thursday in the journal The Lancet Digital Health reaffirms.

Heart disease is the leading cause of death worldwide, and statins can lower LDL cholesterol levels by as much as 60%, reducing a person’s risk of a heart attack or stroke. But despite more than 50 years of data showing the cholesterol-lowering medications are safe, many people are still hesitant to take statins, fearing side effects.

Less than half of the some 50 million people in the United States who could benefit from statins use them, and up to one-third of people never fill their statin prescriptions. And it’s not uncommon for people to stop taking the drug soon after it’s prescribed: Research has shown that about 40% of people prescribed a statin quit taking the drug within three months.

“There is a huge worry in the general population about these drugs based on rare side effects,” said Dr. Nishant Shah, a preventative cardiologist at Duke Health in Durham, North Carolina, who was not involved with the latest research.

In the new study, British researchers developed a tool that can help doctors predict their patients’ risk of statin side effects, including muscle disorders.

These include myopathy, a broad term for conditions that affect muscles and cause soreness, weakness and fatigue; myalgia, which refers to muscle pain; and rhabdomyolysis, a dangerous condition in which muscle tissue rapidly breaks down and toxins leak into the blood.

Rhabdomyolysis can be deadly.

The new study, which used medical record data from nearly 6 million adults in the United Kingdom, found that only about 0.04% of people had a 10-year risk of statin-related serious muscle disorders above 10%.

That’s even lower than previous figures, including from an American Heart Association report, which put the rate of myopathy at less than 1% and the rate of rhabdomyolysis at less than 0.1%.

“Even if you increase that tenfold, that is still a very tiny risk,” said Dr. Bart Duell, a professor of medicine at Oregon Health and Science University in Portland, who co-authored the AHA report but was not involved in the new research. The risk of muscular side effects “really isn’t a reason to not use statins,” he added.

In clinical trials, people taking a statin were slightly more likely to report mild muscle pain than people taking a placebo, but in the majority of those cases, the muscle pain had been caused by something other than the drug.

While patients should be aware of potential side effects for any medication, experts said many overestimate the risk of statins.

“In the 40 years I have been practicing I have never admitted a patient to the hospital from a muscle disorder associated with statins,” said Dr. Steve Nissen, chief academic officer of the Heart, Vascular & Thoracic Institute at Cleveland Clinic, who was not involved with the study. Nissen consults for statin-makers AstraZeneca, Bristol Myers Squibb, Novartis and Pfizer but does not receive financial compensation.

Misinformation fueling fear

Statins — including atorvastatin (Lipitor), rosuvastatin (Crestor) and simvastatin (Zocor), among others — are some of the most widely prescribed and most studied drugs in the world.

“It’s unclear to us why statin side effects draw so much attention compared to other drugs,” said study co-author Ting Cai, a research fellow at the University of Oxford Nuffield Department of Primary Care Health Sciences in the U.K.

Shah, of Duke Health, said the belief that statins are more dangerous than they are stems from a confluence of factors.

“There is a lot of social media messaging out there about it, there’s medical misinformation on non-peer-reviewed websites out there, there are just word of mouth concerns, anecdotal stories of maybe family members having issues,” Shah said. “It all kind of adds to the concern and then people communicate and communicate until that belief is widely spread.”

Duell said patients need to weigh the risks and benefits for any medication.

“For someone who has high cholesterol and maybe a family history of heart disease, the very small risk of side effects is hugely overshadowed by the benefits of lowering cholesterol with medication,” he said.

He added that if people start taking a statin and have any concerns, they should tell their doctor.

“There’s a huge gap between being normal before the statin and having that severe complication, so our goal is always to intervene before there is any severe injury such as muscle breakdown,” he said.

Doctors can always take a person off a statin to see if the side effects such as mild muscle pain go away, or reduce the dose. Statins are not the only cholesterol-lowering drugs available.

“Statin side effects get talked about as if it is a done deal, but a couple important points are that almost all of the side effects are dose-related. It’s not always a yes or no answer, taking or even starting on a lower dose can minimize risk,” Duell said.

Personalized statin risk

The new tool was designed to be used by clinicians during appointments to be able to better predict an individual patient’s risk of developing rare but severe muscle disorders if they take statins.

“Often, people read numbers based on a whole population, or an anecdote about someone who had complications, but they don’t know what will happen to them based on their personalized information, their age, lifestyle and other health conditions,” Cai said.

Her team was careful to separate out mild muscle symptoms, which are more commonly reported, from myalgia and rhabdomyolysis.

“These more serious outcomes are what you want to take into consideration when considering taking statins,” she said.

It is far from the only tool available to calculate personalized statin risk. The American College of Cardiology has a tool that allows clinicians to evaluate a patient’s risk of developing side effects depending on the dosage and specific drug they are taking.

Some people do have a higher risk of side effects from statins, including people with kidney disease and people taking certain medications. Vitamin D deficiency can also cause muscle soreness when people take statins, Nissen, of the Cleveland Clinic, said.

Duell said people should be reassured about safety. “The horror stories people talk about are very unlikely to occur,” he said.