November 7, 1995
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HIV-positive men who lose too much weight before developing AIDS are at risk for dying sooner than those HIV-positive men who maintain their weight, according to a study by researchers at the Johns Hopkins University School of Public Health. The effect of weight loss on survival time occurs even if these men regain some of their lost weight.
"This is the first study of its kind to show that moderate weight loss before a diagnosis of AIDS is, by itself, associated with a reduced survival time after the onset of AIDS," says John Palenicek, M.P.H, a doctoral student and the lead author of the paper.
The National Institutes of Health-sponsored study found that HIV-positive men who lose more than 10 percent of their body weight three to nine months before developing AIDS are up to 50 percent more likely to die sooner those who maintain their weight.
Increased risk of death due to wasting--the loss of enough weight to cause illness--is caused in part by an increase in the body's metabolic rate. AIDS-related health problems, such as infections, are not the only factor, according to Neil Graham, M.D., associate professor of epidemiology and senior author of the paper. This work is described in the November issue of the Journal of AIDS.
Metabolic rate is the speed with which the body burns up food. Severe diarrhea and opportunistic infections that strike AIDS patients whose immune systems are crippled can overwhelm the person's ability to maintain their weight, Graham says.
"The occurrence of wasting late in AIDS has already been shown to predict early death," Graham says. "This new research shows that moderate weight loss in infected individuals prior to AIDS can also predict shorter survival."
The wasting syndrome caused by the high metabolic rate is somehow driven by the interaction of the immune system with the AIDS virus, according to Graham. In addition, tumor necrosis factor (TNF), a protein released by the immune system, may contribute to weight loss, Graham says. So developing a treatment that blocks or destroys TNF might help prevent wasting.
"I think the way to stop wasting is by having better treatment to slow the virus, as well as by using TNF blockers," says Graham.
The study involved 962 individuals examined semiannually for up to 8.5 years as part of the Multicenter AIDS Cohort Study (MACS) of gay and bisexual men in Baltimore/Washington, D.C., Chicago, Los Angeles and Pittsburgh.
Other authors of the study include Alfred Saah, M.D. (Johns Hopkins), John S. Oishi (University of California, Los Angeles), Lawrence Kingsley, Dr.P.H. (University of Pittsburgh), and the Multicenter AIDS Cohort Study.
The study was supported by the National Institute of Allergy and Infectious Diseases.