Sexual risk behaviour doesn’t increase in injecting drug users who start HIV treatment

There is no evidence that starting antiretroviral therapy leads HIV-positive injecting drug users to have more risky sex, Canadian researchers report in the online edition of AIDS. There was no increase in reported sexual activity, unprotected sex, or number of partners.

“Concerns regarding the expansion of access to ART [antiretroviral therapy] for IDU [injecting drug user] populations due to fears of increased HIV risk behaviour in the period following ART initiation are unsupported,” comment the investigators.

Treatment with combination antiretroviral therapy can significantly increase the prognosis of HIV-positive individuals. Such treatment can also dramatically reduce the risk of transmission of the virus to HIV-negative individuals.

HIV treatment can work well in injecting drug users. However, some doctors are reluctant to initiate treatment in drug users. This is because of a fear that this group of patients may not adhere to their treatment.

Moreover, some research has pointed to increased levels of sexual risk taking amongst individuals after they start HIV treatment.

Therefore investigators from AIDS Care Cohort to Evaluate Exposure to Survival Services (ACCESS) in Vancouver, British Columbia, undertook a prospective study that involved 457 HIV-positive injecting drug users. All completed a baseline interview about their sexual behaviour in the previous six months. A total of 197 of these people started HIV therapy, and then completed another interview about their sexual activity six to twelve months after initiating such treatment. The period of the study was between 1996 and 2007.

At baseline, 72% of patients reported that they had had sexual intercourse in the preceding six months. Recent unprotected anal or vaginal intercourse was reported by 35% of individuals, and the median number of reported sex partners was one.

There was no evidence that starting HIV treatment increased sexual activity. Just over a quarter (51) of the patients who had initiated antiretroviral therapy reported any sexual behaviour in the preceding six months.

Moreover, starting treatment with anti-HIV drugs did not increase the risk of engaging in unprotected sex. Anal or vaginal sex without a condom was reported by 17% of patients in the six to twelve months after the initiation of antiretroviral therapy.

Nor did the initiation of HIV treatment increase the risk of having multiple sex partners. Just over a quarter of individuals taking antiretroviral therapy reported having two or more sex partners in the six to twelve month period after they started this treatment.

The investigators then performed a series of sensitivity analyses. They found no evidence that a higher CD4 cell count after starting treatment was associated with either unprotected sex or a greater number of sex partners.

Nor did sexual risk behaviour increase in the longer term. There was no increase in overall sexual activity in the two years after HIV treatment was started, and the proportion of patients reporting unprotected sex or multiple partners remained stable.

“ART initiation was not associated with increases in sexual activity or risk behaviour. Given these findings, concerns regarding potential increases in or resumption of sexual risk behaviour among IDUs following the initiation of HIV therapy appear to be unfounded,” comment the investigators.

However, the investigators did find other factors were associated with sexual risk taking in the period after HIV treatment was started. Unprotected sex was associated with having a partner (p < 0.001), sex work (p < 0.001),  and syringe sharing (p < 0.001). Having multiple partners was associated with older age (p < 0.001), female sex (p < 0.001), crack or heroin use (both p < 0.001), and syringe sharing (p < 0.001).

The investigators “recommend the immediate implementation and evaluation of novel programmes to reduce barriers to HIV care and increase uptake of ART among IDUs”.

Marshall BDL et al. No evidence of increased sexual risk behaviour after initiating antiretroviral therapy among people who inject drugs. AIDS 24: online edition, DOI: 10. 1097/QAD.0b013e32833dd101, 2010.