HIV-positive women who regularly use crack cocaine are three times as likely as non-crack users to die of AIDS-related causes, even if they adhere to their prescribed antiretroviral (ARV) regimen, according to a multi-city study reported in the July 11 issue of AIDS. Infrequent users of crack cocaine are also more likely than nonusers to develop new AIDS-defining illnesses.

Despite numerous laboratory studies indicating that crack cocaine can have profound negative effects on immune system function, there have been very little data from studies involving people living with HIV, notably HIV-positive women, connecting the drug with more rapid disease progression. There has been one major study in HIV-positive male crack users.

The sobering confirmation comes from a study of 1,686 HIV-positive women enrolled at six U.S. clinics participating in the Women’s Interagency HIV Study (WIHS). According to the report, authored by Judith Cook, PhD, of the University of Illinois in Chicago and her WIHS colleagues, 80 percent of those enrolled were women of color, approximately 25 percent were infrequent (intermittent) crack users and approximately 3 percent were regular (persistent) crack users.

Between September 1996 and September 2004—years in which combination ARV therapy was available—there were 419 deaths, including 197 due to AIDS-related causes. Approximately 89 percent of the non-crack users and 90 percent of the infrequent crack users were alive eight years after entering the study, compared with 65 percent of the regular crack users. Even when the researchers factored in the length of time the women had been living with HIV, the effect of having a CD4 count below 200 upon entering the study, and the strictness with which the women adhered to their ARV therapy, the women regularly using crack were much more likely to be dead within eight years.

Rates of AIDS-related diseases, including bacterial pneumonia, pneumocystis pneumonia (PCP), herpes simplex virus, candidiasis, cryptosporidiosis, dementia, wasting syndrome and tuberculosis were higher—and developed much more rapidly—in crack users compared with non-users. Cook’s group also found that the time to a new AIDS-defining illness was significantly shorter among women using crack: 2,305 days for intermittent users and 2,211 days for persistent users, compared with 2,592 days for nonusers.

The authors also report that even during times in which regular and infrequent users of crack were abstaining from the drug, CD4 counts were lower and viral loads were higher, compared with the HIV-positive women who never used crack.

In conclusion, Cook’s team reiterates that theirs is the “first study to show that use of crack cocaine in a large, national cohort of HIV-positive women is…associated with subsequent deterioration in immune status, failure of virologic suppression, development of AIDS-defining conditions and [death] due to AIDS-related causes,” even among those who reported strict adherence to ARV therapy. “Likely confounds such as heroin use, injection-drug use, tobacco smoking, hepatitis C virus coinfection and depression do not appear to account for these significant associations,” they add. “Unlike prior research on a predominantly male sample, we did not consistently find that progression was less likely during periods of abstinence among female crack users, providing support for the notion that effects of cocaine on the immune system may vary by sex, as others have suggested.”