November 25, 2013
A low-cost blood test may help inform HIV care providers on the accuracy of a self-reported new HIV diagnosis, according to recently published U.S. research. The research also provides a stark reminder that self-report alone may not be sufficient for differentiating recent from prior HIV diagnosis, particularly when enrolling volunteers in studies.
The findings, first published online last month in Clinical Infectious Diseases, are based on an examination of samples from HPTN 061, a study exploring interventions to reduce HIV incidence among black men who have sex with men (MSM).
A nationwide collaboration of researchers led by Mark Marzinke, Ph.D., and colleagues at the Johns Hopkins University School of Medicine noted that of the 1,553 men enrolled in HPTN 061, 155 who were HIV infected reported no previous diagnosis -- yet 83 of them had a low viral load (less than 1,000 copies/mL) at enrollment, which was suggestive of some level of virus control.
The test revealed that 71 of the 83 men -- 86% -- had detectable levels of at least one of the 15 antiretrovirals, despite self-reporting that they had not been previously diagnosed.
Among these 71 men, samples from 65 of them showed the presence of an NNRTI or protease inhibitor; this would seem to discount the possibility that they were receiving pre-exposure prophylaxis (PrEP), which typically involves only the use of NRTIs. Based on these findings, the HPTN 061 study administrators reclassified the 65 volunteers as "previously diagnosed" rather than "newly diagnosed."
"A variety of factors may influence the decision not to disclose prior HIV diagnosis when one is being considered for participation in a research study," the authors write. For instance, a desire to participate in the study (and gain access to the clinical care or other incentives it provides) despite not meeting entry criteria may motivate a patient to stretch the truth regarding his serostatus awareness. Alternately, concerns regarding stigma and wider disclosure of his status (to sexual partners, family or others in his personal network) may have led some of the men to avoid admitting their prior status, the authors suggest.
Meanwhile, the authors acknowledge that some of the test results could potentially be "false positives" of a sort, due to the possibility that enrollees were genuinely unaware of their infection but had been taking PrEP or post-exposure prophylaxis drugs. (Offsetting that possibility was the potential for this substudy to have missed some previous diagnoses, due to the fact that the only plasma samples examined were from the subset of patients with a low baseline viral load.)
The authors concluded:
Our findings demonstrate the importance of using an objective, biomedical measure in addition to self-report to distinguish between previously diagnosed and newly diagnosed HIV infections. Further studies are needed to understand why some participants may choose not to disclose their HIV status when enrolling in clinical trials. [Antiretroviral] drug testing may also be useful in surveillance studies and other studies assessing the frequency of undiagnosed HIV infection.
They added that this form of antiretroviral drug testing may also prove useful for adherence monitoring, both within real-world clinical settings and research studies.
Myles Helfand is the editorial director of TheBody.com and TheBodyPRO.com.
Follow Myles on Twitter: @MylesatTheBody.
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