Millions of people take statin drugs to lower their cholesterol levels. And there's been an even bigger push to use them to prevent heart disease since the cholesterol-busting statin drug Crestor was approved by the U.S. Food and Drug Administration as a way to stave off cardiovascular disease in those who don't yet have it.
But new research may throw into question exactly who is at enough risk for heart problems to justify taking the medications – and who might be better off skipping them.
On the one hand, the drugs have been shown to lower levels of dangerous LDL, or "bad," cholesterol. And they are fairly inexpensive. On the other hand, they do carry rare but serious side effects, including the breakdown of muscle tissue, memory loss and a nervous system malfunction called neuropathy.
Delores Wyse wonders if she should be one of the people who skips them. She completely baffled her doctors in October when she had a heart attack, despite that fact that she never had any risk factors for heart disease. She currently takes several drugs to help protect her heart, and one of them is simvastatin.
"I never had high cholesterol, never had high blood pressure or diabetes," said Wyse, who lives in Maui, Hawaii. "I'm also not overweight. I exercise and always eat healthy. My doctors still consider me extremely low risk for heart disease."
A group of British researchers found that people who are at low risk for heart disease -- in this case, those who have never had heart disease and aren't likely to develop it -- may not benefit very much from taking statins. In a report published in The Cochrane Database of Systematic Reviews, a group of British researchers reviewed 14 studies with more than 34,000 low-risk participants who took statins for at least a year and found that there is a very low likelihood of death from any cause.
"Cochrane Review guidance is helpful in highlighting that the current evidence does not support use of statins below a 1 percent annual all-cause mortality risk or an annual CVD [cardiovascular disease] event rate of below 2 percent," the report said. Experts say this level of risk is extremely low.
The researchers also found that statins lowered cholesterol levels, reduced the number of procedures required to improve or restore blood flow through the heart and reduced the number of strokes. Despite these benefits, the authors say the use of statins doesn't really improve people's quality of life, and that a number of the trials they analyzed were significantly flawed. As a result, they say "caution should be taken in prescribing statins for primary prevention among people with low cardiovascular risk."
In an accompanying editorial, another British researcher said those flaws include the selection of favorable outcomes to make drugs appear move effective and pre-existing relationships between study authors and pharmaceutical companies.
But a number of other doctors told ABC News they disagree with several of the review's conclusions. They say that most doctors do not prescribe statins for people whom they consider very low risk, and also say it's difficult to define "low risk."
The report's critics also say that the studies clearly show the benefits of statins for reducing the risk of developing heart disease. Among the findings the review highlighted were that among people who used statins, all-cause mortality decreased by 17 percent and cardiovascular disease-related outcomes, such as heart attacks, decreased by 30 percent.
"There are highly significant benefits on death, heart attack and revascularization, and then they tell people they see no benefits? I just don't get it," said Nissen.
"We're not prescribing statins for everyone who is low risk. But the primary prevention where the benefit is huge is in those 55 and older whose cholesterol is a bit high. They have a documented benefit," said Dr. Chris Cannon, associate professor of medicine at Harvard Medical School.
Dr. James Stein, professor of medicine at the University of Wisconsin-Madison said the study's authors point out that there are minimal adverse side effects associated with the use of statins, which he said is remarkable considering the numerous number of medical treatments out there.
Experts also argue that longer-term studies could possibly have shown a greater magnitude of statin benefits since heart disease usually takes a very long time to develop.
Defining 'Low Risk' is a Major Issue
The review's authors define low risk as having a less than 1 percent chance of dying from any cause or having a less than 2 percent chance of suffering some sort of cardiovascular event. But there are other ways of determining a person's risk of developing heart disease, so experts suggest "low risk" may need to be better defined, especially among the elderly, whose age puts them at higher risk.
"According to [guidelines from the National Heart Lung and Blood Institute] anyone with a risk of having a 'hard' CHD [coronary heart disease] event of less than 10 percent over a 10-year period is low risk," said Dr. Christie Mitchell Ballantyne, associate chief of the Section of Atherosclerosis and Lipoprotein Research at Baylor College of Medicine in Houston. Ballantyne said she gets research support and consults for a number of companies that make statins.
There is also the United Kingdom's National Institute for Health and Clinical Excellence guidelines, which promote treating individuals with a 20 percent or greater risk of developing cardiovascular disease in 10 years, as well as the Framingham risk scores that estimate the risk of heart disease in 10 years.
Statins Also Very Cost-Effective
Experts also say that a number of statin drugs that are available in generic form, cost just $4 a month.
"I would bet that such therapy will prove to be cost-effective in adults at least 50 years of age since statins such as pravastatin and simvastatin are now so inexpensive," said Dr. Roger Blumenthal, professor of medicine at the Johns Hopkins University School of Medicine in Baltimore.
He also argues that preventing heart disease earlier will save money.
"[N]onfatal heart attacks, strokes, and revascularizations and the associated hospitalizations for these nonfatal events are extremely costly. Moreover, one needs to consider the morbidity leading to loss of jobs and possible nursing home placements for advanced heart failure due to weakened heart muscles from heart attacks as well as from strokes."
Delores Wyse is a bit more skeptical. She'd like to see more evidence that statins really do work for people like her.
"Now, I think I really take these drugs because I worry that if I don't, I may have a heart attack again, but I would be interested in knowing more about them because for people who are low-risk, there's not a lot of information out there."