- Category: HIV Prevention
- Published on Sunday, 07 July 2013 00:00
- Written by Roger Pebody
One of the anxieties in relation to treatment as prevention is that it may discourage people with HIV from using condoms and other prevention methods. However, a meta-analysis has found no increase in risk-taking among people taking antiretroviral treatment, researchers reported at the 7th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention (IAS 2013) this week in Kuala Lumpur last week.
In fact, the study, by Joseph Doyle and colleagues, found that people on treatment had less unprotected sex and fewer sexually transmitted infections.
One important caveat is that the researchers examined studies from all parts of the world and at any time since the introduction of antiretroviral therapy (ART), with only some of them gathering data in recent years. However, understanding of the meanings and benefits of taking HIV treatment are changing. No studies related to people specifically prescribed antiretrovirals for prevention purposes.
The researchers identified all previous studies that met predetermined criteria and pooled their results. Relevant studies were of HIV positive adults, with some taking ART and some not, that provided information on unprotected sex, diagnoses of sexually transmitted infections, or unsafe injecting. The methodology of the Cochrane Collaboration was followed.
They found 55 different studies that provided data on self-reports of unprotected sex or inconsistent condom use, with over 30,000 total participants. The pooled data showed that people on treatment were 28% less likely to report unprotected sex than people not taking treatment (odds ratio 0.72). However, there was considerable heterogeneity in these results -- the findings varied considerably from study to study.
Moreover, people taking treatment were less likely to report unprotected sex with a person of unknown or negative HIV status (odds ratio 0.57).
They found 11 studies with around 16,000 total participants that had information on diagnoses of sexually transmitted infections. Again, the results suggested that people on treatment were less likely to acquire an infection (odds ratio 0.58), although this was not quite statistically significant.
These results were again quite heterogeneous, but essentially because of a single study with very different results from the others. The researchers felt justified in excluding this one from a further analysis. With this study removed, the results became statistically significant (odds ratio 0.48).
Only 4 studies, with 1600 total participants, provided information on unsafe injecting practices (lending, borrowing, or re-use syringes). This analysis showed that people on treatment were neither more nor less likely to have unsafe practices (odds ratio 0.90, 95%).
The researchers say that the lower levels of risk behavior reported by people on treatment should be interpreted cautiously, as this data cannot tell us anything about the causal relationships.
While it is possible that the counseling and support associated with engagement with healthcare help individuals to limit their risk taking, it is equally possible that the causation could run the other way -- people who have more stability in their lives or who are more risk averse may be more likely to go on treatment.
But the data remains reassuring. "Strategies to scale up use of treatment in the context of care are unlikely to adversely affect risk-taking behavior," the authors concluded.
JS Doyle, L Degenhardt, A Pedrana, et al. Meta-analysis of effects of antiretroviral therapy use on sexual and injecting risk-taking behaviour. 7th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention. Kuala Lumpur, June 30-July 3, 2013. Abstract WEPDB0105.