AIDS progression depends on quality of care.

One of the many mysteries of AIDS is why the disease seems to develop more rapidly in individuals from certain groups, especially women and blacks. A new study suggests that the link between the progression of HIV infection and factors such as race and sex has nothing to do with biology. Rather, unequal access to medical care may explain why some HIV-infected people stay healthier and survive longer than others.

Understanding this association is important, says Richard D. Moore of the Johns Hopkins University School of Medicine in Baltimore, so that "people don't go off on wild goose chases for biological" links that don't exist. Moore and his colleagues Richard E. Chaisson and Jeanne C. Keruly report their findings in the Sept. 21 New England Journal of Medicine.

The group analyzed demographic and health information from 1,372 people who went to the Johns Hopkins HIV Clinic for treatment over a 5-year period. They continued to track the patients to determine how quickly HIV infections developed into AIDS.

The researchers measured the individuals' disease progression by counting their CD4 cells, immune system cells killed off by HIV (SN: 3/18/95, p.172). Among people with comparable initial CD4 counts, the scientists found no association between rates of survival or development of AIDS and such factors as race, sex, use of injected drugs, income, education, and insurance coverage. Therefore, correlations of this sort found in other studies probably reflect differences in access to medical care, the researchers say.

Although previous findings have suggested similar conclusions, the strength of the Johns Hopkins study lies in the group examined, says Paul A. Volberding of the University of California, San Francisco, and the AIDS Program at San Francisco General Hospital. "They're looking at a well-characterized patient population," he says. "It has the advantage of being a demographically diverse group of people receiving care at a single site."

The breadth of the subject pool lends weight to the idea that access to care predicts survival more reliably than other characteristics. "If there were biological differences in disease progression based on these demographic factors, we probably would have seen differences in our [group]," Moore says. "When you control for access, the sociodemographic disparities aren't there."

Some factors did correlate with lower or higher rates of survival, but none of these was inconsistent with previous findings, Moore says.

For example, people diagnosed with AIDS before seeking care at the clinic or who had previously received AZT (zidovudine) therapy had a lower rate of survival. These factors, Moore says, singled out patients who had more advanced HIV infections initially, which in turn affected their chances of survival. Older patients also had lower survival rates, perhaps because their bodies are less able to cope with the lower immunity to other diseases caused by HIV infection.

On the other hand, patients who received drugs to combat AIDS-related pneumonia or who began taking AZT after arriving at the clinic had a higher rate of survival.

Amid the shifting opinions over the biology of AIDS, this study turns the focus back on the providers of care, Volberding says. "Instead of being a passive issue of one group progressing more rapidly than another, it puts the burden back on the health profession," he adds. The study shows that "one's health behaviors, apart from access to medical care, probably don't influence how the virus progresses. It reinforces the idea that HIV itself really doesn't discriminate."