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Press Release
Antibiotic fails to show long-term benefit in Gulf War illnesses trial
For Release July 20, 2004
The antibiotic doxycycline did little better than placebo over 12 months in a study of nearly 500 veterans with Gulf War illnesses, report Department of Veterans Affairs researchers and colleagues in the July 20 Annals of Internal Medicine.
The trial, conducted at 26 VA medical centers and two Department of Defense sites, was prompted by the theory that Gulf War veterans' illnesses (GWVIs) may be caused by mycoplasma, a type of bacteria that has been studied as a possible cause of chronic fatigue syndrome and fibromyalgia. The effort, funded with $7.8 million from VA and $5.2 million in drugs and placebos from Pfizer, was the largest clinical trial yet to test whether antibiotics could ease Gulf War veterans' health problems.
The symptoms of GWVIs resemble those of chronic fatigue syndrome: fatigue, pain, respiratory problems, depression, poor concentration, memory loss. Studies have confirmed that service men and women deployed to the Persian Gulf in 1990 and 1991 are at higher risk for the condition, but researchers are still exploring possible causes. Most theories center on infections, exposure to environmental toxins, or stress reactions.
No treatment has emerged as highly effective, though a VA-DoD trial published last year in the Journal of the American Medical Association did find some benefits for exercise and cognitive behavioral therapy.
In the new trial, researchers enrolled 491 veterans who had symptoms of GWVIs and whose blood tested positive for mycoplasma DNA.
Half the participants received doxycycline, the other half placebo. While the antibiotic group showed greater improvements in physical health after three months, the differences evened out after six months. After a year, only about one in five veterans had improved significantly in their physical functioning, regardless of which group they were in. Those receiving the antibiotic, as expected, experienced higher rates of side effects such as stomach upset and sensitivity to light.
Researchers also saw no difference in pain, fatigue, cognitive function or mental health between the two groups.
The investigators say they don't know whether participants in the study had active mycoplasma infection. The presence of mycoplasma DNA in the blood merely indicates past exposure to the pathogen. Interestingly, almost all study participants had cleared the germ from their blood by the study's conclusion, regardless of whether they took the antibiotic or not. The researchers believe the level of infection may have influenced whether doxycycline was effective.
"Antibiotics are clearly effective for true mycoplasma infections," said study co-author Lisa L. Dever, MD, an infectious-diseases specialist at the East Orange, N.J., VA Medical Center. "For example, we know that in cases of mycoplasma pneumonia, doxycycline shortens the duration of people's illness."
Mycoplasma are tiny bacteria that live in the mouth, urinary tract and other areas of the body. They reproduce on their own, without a host cell. They do not have a cell wall, like most bacteria, and their metabolism periodically slows down. These factors may enable the pathogen to evade the knock-out punch of conventional antibiotics.
Since 1994, the departments of Defense, Veterans Affairs, and Health and Human Services have spent about $247 million on research relating to the health effects of service in the Gulf War. VA recently announced plans to step up funding for studies on the health effects of deployments, including the Gulf War, the current Iraq War, and operations in Afghanistan and elsewhere.
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