The development of antiretroviral therapies (AVT) in the 1990s transformed HIV/AIDS from a terminal illness to a chronic disease. Today there exist dozens of drugs that target different phases of the retrovirus lifecycle, inhibiting the replication of the HIV-1 virus. AVT lowers viral loads, increases CD4 counts, and reduces the probability of clinical and transmission events over time. In HIV patients under treatment life expectancy actually approaches that of unaffected individuals (Sigham, et al. 2010). The importance of adherence is therefore paramount to health and to the transmission of the virus. Two of this week’s readings introduce research into links between AVT adherence and risk taking behavior. The first study (Holsted, et al. 2011) shows that group motivational interviewing promotes adherence and reduces risk-taking behaviors. A second study by the same group (2011) shows that adherence and risk taking behaviors closely correlate to one another in HIV patients. A third reading (Cohen, et al. 2011) determined that early initiation of ACT can prevent HIV-1 infection. Taken together, these papers indicate the importance of understanding and adjusting behaviors (risk taking and adherence specifically) for future progress towards preventing and treating HIV/AIDS.
A piece of data I found surprising was the extent of patient non-adherence to AVT. In her two studies Holsted reported that only 74.2 and 74.6 percent of prescribed doses were taken (and only 58.9 percent taken on schedule). Cohen reported similar levels of adherence; in two study groups 79 and 74 percent of patients adhered to the regimen of 95% of doses taken. In these studies, then, one in five patients was unreliable in taking their medications. To me this seems a remarkably high number. Not only does low adherence heighten the risk of a transmission or clinical event, it also raises the possibility of new multiple-drug-resistant virus strains. Meanwhile, the benefits of ACT are plainly demonstrable. What I take away from these numbers is that, as Felicia Guest said in Monday’s discussion, behaviors are very difficult to change. It also seems that impressing patients with the meaning of risk is also a significant clinical challenge.
If adjusting behavior, then, is critical to making next steps in fighting and controlling HIV/AIDS, a major obstacle might be the difficulty of communicating risk and its implications. Risk, after all, is a quantified abstraction, usually appearing as a probability. How does a patient know how to make meaning of a percentage or number, and then to apply it to life decisions? Particularly when risk accumulates over many years (or an entire lifetime), it may be very hard to understand the consequences of a behavior or decision in terms of risk. Perhaps if care providers were better able to communicate the meaning and implications of risk, progress could be made towards adjusting behaviors such as adherence. I look forward to learning more about how these kinds of conversations are developed between patient and care providor.