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Cholesterol-Lowering Drugs Tied to Flu Survival
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Study: People Taking Statins Are Less Likely to Die From Influenza
By Brenda Goodman, MA
Reviewed by Laura J. Martin, MD
But don't trade a prescription for statin pills for a flu shot or other protections just yet. Researchers say their findings need to be confirmed in a larger clinical trial.
The study compared the fates of slightly more than 3,000 people hospitalized with flu. About one-third of them were taking statins before or during their hospitalization.
Of those in the study, 5% (151 people) died within a month of their diagnosis.
But people taking statins were about 41% less likely to die after getting the flu than people who were not taking statins.
That was true even after researchers took into account a host of factors that could have played a role in a person's recovery. They looked at age, race, and whether or not a person had gotten a flu shot. They noted chronic health problems like lung, heart, or kidney disease. They also checked to see if people were promptly prescribed antiviral medications to fight the flu.
The study is published in The Journal of Infectious Disease.
Should Statins Be Tested Against the Flu?
The finding echoes two previous studies that also found that statins were associated with some protection from the worst flu outcomes, including pneumonia, hospitalization, and death.
Researchers say that's enough evidence to test statins in a large clinical trial to see if they can help prevent flu deaths.
There are quite a few caveats to a study like this that relies on an observed association, says researcher Ann R. Thomas, MD, MPH, a public health doctor with the Oregon Public Health Division, in Portland. "But I think it's good enough that someone will invest in a clinical trial."
Not everyone agrees that would be worthwhile strategy.
"At the end of the day, I'm not convinced that statins are protective," against the flu, says Jeffrey C. Kwong, MD, a scientist with the Institute for Clinical Evaluative Science in Toronto.
Kwong has also studied statin use in people who get the flu. He was not involved in the current research, though he says it is well done.
He says his own experience suggests that other factors were probably behind the drugs' supposed benefits.
"The people who receive statins are just inherently different from people who don't receive statins," he says.
One example that's often seen in studies of this kind is something called the health user effect. People who take preventive medications like statins may simply be more interested in taking care of their health than people who don't take them. That could also mean they are in better overall health and are therefore less likely to die of the flu.
Researchers say they couldn't find any evidence of the healthy user effect in this study.
Kwong says it would be impossible to account for every possible difference that could skew the results.
"The statistical methods we have are generally inadequate to remove the [outside influences] that are there," he tells WebMD.
How Statins May Fight the Flu
Still, infectious disease experts say it makes some biological sense that statins might make the flu less lethal.
When the flu virus attacks, it can damage the body on two fronts. There's the direct damage caused when the virus kills off cells. Then there's the misery caused by the body's own response to the infection, which can cause dangerously high fevers and swelling of tissues.
Statins are known to have anti-inflammatory effects that may dampen the body's response to the virus.
If used with drugs that stymie the ability of the virus to infect cells, experts say the treatment could potentially deal the flu a potent one-two punch.
"In combination with antiviral drugs, maybe it would be a real advance," says Edward E. Walsh, MD, a professor of medicine at the University of Rochester School of Medicine in New York.
In an editorial on the study, he agrees that a clinical trial is needed to answer important questions.
"The drugs are relatively safe to give," he says. But because most people are on statins long-term, it's not known whether giving them to someone soon after they are diagnosed will do any good.
"The question is whether they could be effective in that setting where you administer them right away," Walsh says.
Preventing flu deaths has long been a public health priority. According to the CDC, studies estimate that between 3,000 and 49,000 people in the U.S. -- many of them elderly -- die each year from complications of the flu.
Thomas says in years where the flu vaccine is in short supply or isn't well matched to the circulating flu strains, or when the virus proves resistant to antiviral medications, it's important to have other treatment options.
"It would sort of be appealing to have another tool in the toolbox," she says.
SOURCES: Vandermeer, M. The Journal of Infectious Diseases, published online Dec. 14, 2011.Walsh, E. The Journal of Infectious Diseases, published online Dec. 14, 2011.Kwong, JC. PLoS One. Published Nov. 30, 2009.CDC, "Key Facts About Influenza," updated Oct. 4, 2011.Ann R. Thomas, MD, MPH, public health physician, Oregon Public Health Division, Portland.Jeffrey C. Kwong, MD, scientist, Institute for Clinical Evaluative Science; family physician, Toronto Western Hospital Family Health Team, Toronto, Ontario..Edward E. Walsh, MD, professor of medicine, The University of Rochester School of Medicine, New York.