February 7, 2017
Research has found that taking HIV treatment (ART) every day exactly as prescribed and directed -- adherence -- generally results in improved measures of health. This occurs because within several months after initiating ART the amount of HIV in the blood usually falls to a very low level -- so low that it cannot be accurately measured with routine lab tests. This low level is commonly called "undetectable." Clinical trials have shown that HIV-positive people who achieve and maintain an undetectable viral load do not transmit the virus to their sexual partners.
Adherence is important when trying to achieve benefits that accompany the treatment of nearly all conditions. In HIV disease, studies have found that very high levels of adherence (95% or greater) are needed to maintain the health and prevention benefits that come with ART. As excellent adherence is essential for the success of HIV treatment and prevention, teams of researchers continue to study it.
Researchers at the B.C. Centre for Excellence in HIV/AIDS and elsewhere in Vancouver have been collecting information related to treatment adherence from HIV-positive people over a period of 15 years. Their analysis of this data has found that the proportion of people with optimal adherence to ART was significantly less in women (57%) compared to men (77%).
Readers should note that the B.C. study was not designed to uncover the reasons for these differences in adherence. But it is a good first step toward designing a study and writing and submitting a funding proposal to funding agencies. Hopefully such a proposal will get funded so that research can be done with HIV-positive women in B.C. to better understand the drivers of poor adherence. The results of such a study could then be used to develop ways to enhance existing services for HIV-positive women and to support their adherence.
Assessing adherence directly is time consuming and expensive. Therefore, researchers with the B.C. team assessed adherence indirectly by accessing pharmacy records to determine if prescriptions were refilled in a timely manner. This indirect method of assessing adherence has been validated in previous studies with HIV-positive people.
The B.C. team assessed adherence at intervals of six months. Here is an example provided by the researchers:
"In a six-month period, or 183 days, an individual may be seven days late to fill their prescription. In this case, adherence would be calculated by dividing 176 days (the period for which the individual has medications) by 183 days, resulting in 96% adherence for the period."
Using pharmacy refill information may seem like an oversimplified way to estimate adherence, as collecting a refill of a prescription could be different from a person's pill-taking habits. However, as mentioned previously, using pharmacy refills as a way of estimating adherence has been validated in other studies and has been linked to a person's viral load. That is, people who had suboptimal adherence based on pharmacy refill data were more likely to have a detectable viral load.
In an era when funding for HIV research is not increasing significantly, it is likely that more scientists will make use of pharmacy refill data to estimate overall adherence in whatever population is being studied.
For their analysis, researchers collected data from 4,534 HIV-positive people between January 1, 2000 and December 31, 2014. On average participants were monitored for about five and a half years.
Using a definition where optimal adherence was 95% or greater, the researchers found that, overall, the distribution of optimal adherence was as follows:
This difference was statistically significant; that is, not likely due to chance alone.
The findings from the B.C. study are broadly similar to what has been reported by other researchers who have reviewed adherence to ART in other high-income countries.
Although the present B.C. study was not designed to uncover reasons for poor adherence, the B.C. researchers suggested that women in their study might have been vulnerable to factors that impacted adherence. According to the researchers, such factors would have arisen from circumstances that intersected with their race/ethnicity, a history of abuse, and injection drug use. We now explore some of these issues.
The B.C. researchers observed that, overall, Indigenous people were less likely to be highly adherent to their treatment than non-Indigenous people. In explaining this link, they advanced the following points relevant to the Canadian context:
The researchers noted: "Poorer health outcomes among Indigenous people, such as HIV-related [illness and death], cannot be discussed without connecting these conditions with Canada's history of colonialization, marginalization and criminalization of culture. The negative impact of Canada's colonial legacy can still be observed in the disproportional rates of injection drug use, alcoholism and suicide, in addition to the [continued spread of HIV among Indigenous people]. ... In the context of colonialism, there is a need for culturally competent HIV-related care to support ART adherence and to build trust between Indigenous people and non-Indigenous HIV-care providers."
The B.C. researchers took into account injection drug use to see whether or not this had an impact on adherence. However, for 55% of participants there was no information about injecting street drugs. This lack of information may have inadvertently biased the researchers' conclusions. However, among participants for whom this data was available, gender (in this case being a woman) continued to be the main factor associated with poor adherence.
It is possible that there were issues that affected women that could have had an impact on their ability to adhere to ART. For instance, the researchers put forward the following possibilities:
The researchers said that women with a history of abuse and in the absence of women-centred care may be especially vulnerable to these competing demands on their time, energy and ability to look after themselves.
The power of ART to help reduce the spread of HIV is so tremendous that the United Nations Joint Programme on HIV/AIDS (UNAIDS) has set goals to which cities, regions and countries can aspire by the year 2020. These goals are encompassed in the shorthand phrase 90-90-90:
If Canada is to meet these targets, it will have to intensify efforts working with Indigenous and other populations affected by HIV.
The B.C. study provides the rationale for researchers to develop a proposal for which they then need to secure funding so that they can understand why some people with HIV in that province need help with adherence to ART.
|This Week in HIV Research: Internalized Stigma Decreases Adherence in Women of Color, and Annual CD4 Tests Sufficient For HIV/HCV Coinfection|
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