Cholesterol Busters to Fight Flu?

ST. JULIAN'S, MALTA--A preliminary study suggests that cholesterol-lowering drugs called statins may help prevent serious complications from a flu infection. If that's true, the drugs, which are cheap and easy to produce, would offer a glimmer of hope that poor countries might be able to protect themselves from pandemics.

Over the past decade, researchers have discovered that statins not only lower cholesterol but also reduce levels of immunomodulators called cytokines, dampening inflammation. This is thought to contribute to their protection against cardiovascular disease. It may also explain why in three studies so far, patients on statins appeared to fare better in bacterial infections where inflammation plays a major role, such as sepsis and pneumonia. Because flu viruses trigger cytokine release as well, and complications from flu include heart disease and pneumonia, David Fedson, a retired medical director of Aventis, wondered whether statins might be useful, either as a treatment or prophylactically, when flu is going around. If so, it would "revolutionize pandemic preparedness" and "give hope to developing countries," Fedson says.

At Fedson's urging, clinical epidemiologist Eelko Hak and colleagues at University Medical Center Utrecht in the Netherlands began looking for evidence in a Dutch research database of 60,000 primary care patients. Such data collections are invariably incomplete; whether a patient was tested for flu or bacterial infections often isn't recorded, for instance. Nonetheless, Hak found tantalizing clues, he told the Second European Influenza Conference here on 14 September. During flu epidemics between 1996 and 2003, patients who had had at least two statin prescriptions over the previous 12 months had a 26% lower risk of pneumonia and other severe respiratory ailments. In non-flu seasons, statins didn't reduce the risk, suggesting the drugs offer specific protection against flu complications.

That doesn't position statins as the next generation of flu drugs just yet. The results will need to be confirmed in other patient populations, Hak says; pharmacoepidemiologist Christoph Meier of the University Hospital in Basel, Switzerland, says he will report results from a similar study shortly. Data from old clinical trials with statins should be re-examined, adds Hak, whose colleagues in Utrecht are also planning in vitro studies to determine how statins might have a protective effect. Clinical studies would have to show whether statins should be taken prophylactically--as millions of people do for heart disease--or once a person is exposed to or infected with the flu.

Questions aside, the findings generated interest among meeting participants such as Frederick Hayden, an antiviral expert at the University of Virginia, Charlottesville: "It's definitely something that should be explored."

Related sites
Paper suggesting that statins reduce the risk of severe sepsis
Study showing that statins appear to prevent death from pneumonia
Paper about statins' effect on mortality from bacteremia
Other potential benefits from statins: strengthening bones and preventing Alzheimer's

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