Despite some concerns to the contrary, IV drug abusers who get drug treatment for HIV do not seem to increase their risky behavior, a new study suggests.

In the U.S., injection drug use has directly or indirectly accounted for more than one-third of AIDS cases since the epidemic began, according to the Centers for Disease Control and Prevention.

Injection drug users are at increased risk of HIV both because of their drug abuse - the virus can be transmitted through shared needles or other equipment - and because of their increased rates of risky sexual behavior.

International guidelines say that injection drug users should have universal access to the antiretroviral drugs that can suppress HIV and forestall the progression to AIDS. However, some short-term studies have raised concerns that once these individuals start treatment, they often increase their sexual risk-taking - becoming more likely to forgo condoms or have multiple partners, for example.

But in the new study, reported in the journal AIDS, Canadian researchers found no evidence that injection drug users increased their risky sexual behavior in the six months to one year after starting antiretroviral therapy.

The study included 260 injection drug users in the province of British Columbia who began anti-HIV treatment between 1996 and 2008; of those, 197 completed interviews before starting drug therapy and at least once afterward, including one done six to 12 months after their treatment began.

During those six- to 12-month interviews, 17 percent of participants reported having unprotected sex in the past six months, and 27 percent said they’d had multiple sex partners.

Overall, the researchers found, study participants were no more likely to report those behaviors than they were before starting treatment or in later interviews over the longer term.

The findings suggest that starting anti-HIV medication does not encourage injection drug users to take additional sexual risks, according to the researchers, led by Brandon Marshall, a Ph.D. candidate at the University of British Columbia in Vancouver.

And, the researchers say, they support efforts to help injection drug users gain better access to comprehensive HIV care and stick with their medication regimen - such as programs that combine HIV therapy with treatment for patients’ drug addiction.

“The main public health implication of our study is that social, economic, and legal barriers to accessing health care must be addressed to ensure the successful delivery of antiretroviral therapy to injection drug users,” Marshall told Reuters Health by email.

He and his colleagues note that their study setting is “somewhat unique,” because in British Columbia, anti-HIV drugs are distributed from a central source, and are free to eligible patients.

However, Marshall said, “we do believe our results are generalizable to other areas, including the United States.”

He noted that all jurisdictions in Canada cover the majority of HIV drug costs. In the U.S., state-run AIDS Drug Assistance Programs help provide medication to low-income, uninsured people with HIV.

The study has its limitations, including its reliance on participants’ self-reported sexual behavior. However, the researchers write, there is no reason to believe that the reliability of participants’ reports would be different after they started HIV therapy, compared with before.

SOURCE:  AIDS, online July 30, 2010.