Core group of patients with drug resistant HIV engaging in risky sex identified by US study

A small minority of HIV-positive patients taking highly active antiretroviral therapy (HAART) have drug resistance and engage in unprotected anal or vaginal sex with partners who are HIV-negative, or of unknown HIV status, according to a US study published in the November 5^th edition of AIDS. The investigators also found that individuals with an undetectable viral load were no more likely to engage in high-risk sexual activity than patients with a viral load above 400 copies/ml.

Studies suggest that between 8 and 24% of newly acquired HIV infections in North America and Europe involve resistant HIV. HIV-positive patients receiving HIV care, and taking HAART are likely to be the major source of these infections. However, little is known about these individuals’ demographic characteristics, behaviour patterns or sexual partners.

Accordingly, investigators in Connecticut conducted a cross-sectional study involving 333 HIV-positive patients with information on CD4 cell count, viral load and antiretroviral resistance.

Patients were asked to complete a questionnaire providing demographic information and details of their sexual activity over the previous three months. In particular, patients were asked to say if they had been sexually active, if this involved penetrative sex, if condoms were used, and if their partner was HIV-positive, HIV-negative or of unknown HIV status. The investigators categorised high-risk sexual transmission behaviour as unprotected penetrative sex with a partner who was HIV-negative or of unknown HIV status.

The majority of patients included in the investigators' analysis were male (54%), heterosexual (79%), and 40% were African American. Heterosexual sex was reported by 47% as their HIV risk activity, with 41% reporting injecting drug use and 9% sex between men.

The majority of patients (178 of 333, 53%) had a viral load above 400 copies/ml, and 121 (68%) of these individuals were taking HAART. In total, 89 patients had resistance to one or more antiretroviral drugs.

Sex during the previous three months was reported by 51% (170) individuals, and 75 individuals said that they had had unprotected anal, oral, or vaginal sex during this period.

A total of 23% of patients reported unprotected sex (which not only included penetrative sex without a condom, but oral sex). There was no difference in the proportion of patients reporting unprotected sex between those with a detectable viral load (22%) and an undetectable viral load (23%). Similarly, there was no difference in the proportion of patients with an undetectable viral load with or without resistance reporting unprotected sex (26 vs. 20%, p = 0.614).

After studying the details of the patients’ sexual histories, the investigators calculated that only 15 individuals (5% of the entire study population), had resistance to one or more anti-HIV drugs and were having unprotected sex with partners who were HIV-negative or of unknown HIV status. The investigators further calculated that these 15 individuals had 149 high-risk sexual events and exposed 28 individuals who were HIV-negative or of unknown status to drug resistant HIV.

Patients with resistant HIV reporting high-risk activity with patients they could potentially infect were younger (40 vs. 44 years, p = 0.036), had a higher level of education (p = 0.07), were more likely to be bisexual (p = 0.001), and have lower mental health scores (p = 0.008). Gender, ethnicity, CD4 cell count, and viral load were not predictors of high-risk activity.

In multivariate analysis controlling for age, mental health, sexual orientation, education and annual income, the only factor which remained significantly associated with high-risk sexual activity with a partner who could potentially be infected with resistant HIV was a low mental health score (p = 0.02).

“These results indicate that there is a substantial opportunity for both sensitive and resistant HIV [transmission] to at-risk partners from patients in care. Among these [333] HIV-positive patients 23% engaged in unprotected sexual behaviour during the previous three months, with a total number of unprotected events exceeding 1000,” comment the investigators.

However, only a small proportion of patients had resistance and engaged in high-risk sexual activities. Nevertheless, “the total number of potential transmission events and partners at risk of acquisition of resistant HIV is quite substantial,” the investigators add.

The investigators note with interest that viral load was not a predictor of unprotected sexual activity and conclude, “results from this study suggest that a likely source of resistant infections is a small core group of patients within the clinic setting that have both resistance and high HIV transmission risk behaviours.” As mental health was significantly associated with risk behaviour “addressing mental health issues may be the key to reducing transmission risk behaviours.”