NCPA - National Center for Policy Analysis


April 22, 2005

Taking antibiotics didn't prevent heart attacks in the most ambitious tests yet of whether wiping out bacteria that thrive in human arteries can protect the heart. The two studies, in the New England Journal of Medicine, involved more than 8,000 heart disease patients. Although antibiotics failed to help people whose arteries are clogged, the disappointing findings did nothing to disprove mounting evidence that heart disease has an infectious component.

In a study by Thomas Grayston of the University of Washington, more than 4,000 patients were given either azithromycin or a placebo weekly for a year:

  • Researchers tracked them to see how many in each group died, had bypass surgery or were hospitalized for severe chest pain.
  • The results were virtually identical in both groups: 446 of those taking azithromycin and 449 of those taking placebo.

In a study by Christopher Cannon of Brigham and Women's Hospital in Boston, nearly 4,200 patients with a heart emergency in the past 10 days were started on an antibiotic called gatifloxacin or a placebo:

  • The patients in this trial, called PROVE-IT, also took a high-dose statin.
  • Patients who took the antibiotic had 5 percent fewer heart attacks and other problems than those taking a placebo, which could have occurred by chance.
  • Patients taking the statin had a 16 percent reduced risk of heart problems.

Experts offered many possible reasons for why the antibiotics failed.

"Maybe we need different antibiotics. Maybe the bacteria are sequestered in white blood cells and we can't get to them. Maybe we didn't treat (patients) early enough. Maybe we focused on the wrong infectious agents," says Jeffrey Anderson of LDS Hospital in Salt Lake City. "All these are possibilities."

Grayston noted that developing a vaccine could keep the bacteria from taking hold.

Source: Steve Sternberg, "Heart disease fails to respond to antibiotics," USA Today, April 21, 2005; based upon: J. Thomas Grayston et al., "Azithromycin for the Secondary Prevention of Coronary Events," New England Journal of Medicine, Volume 352:1637-164, No. 16, April 21, 2005; and Christopher P. Cannon et al., "Antibiotic Treatment of Chlamydia pneumoniae after Acute Coronary Syndrome," Vol.352, No. 16, April 21, 2005.

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