'Stop Describing, Start Intervening': Can the CDC's New Viral Load Data Help Guide HIV Programs?
March 16, 2017
When epidemiologist Kate Buchacz, Ph.D., got up in front of a packed room of researchers and clinicians at the Conference on Retroviruses and Opportunistic Infections (CROI 2017) in February, she was delivering the third of three epidemiological studies from the Centers for Disease Control and Prevention (CDC) describing progress on HIV care in the U.S.
The first came when Sonia Singh, Ph.D., presented data showing that the HIV rate in the U.S. had dropped by 18% overall in the last six years. The second came when Nicole Crepaz, Ph.D., presented data on viral load dynamics among people living with HIV in the U.S. Then came Buchacz's presentation, which showed that the percentage of time people in HIV care spent with viral loads above 1,500 copies/mL had dropped from 37% in 2000 to 10% in 2014.
"The main message here is that, overall, we saw improvements for the whole population, suggesting that the efforts to test [and] diagnose HIV infection sooner, start [antiretroviral] treatment earlier and help patients be retained in care and adherent to their treatment are working over time," Buchacz told TheBodyPRO.com. "I think that's good news."
It's great news, particularly because, while studies such as HPTN 052 and PARTNER showed that a fully suppressed HIV viral load is associated with a negligible risk of transmitting HIV, people who have detectable viral loads less than 1,500 copies/mL also rarely transmit the virus, she said. As a result, an even lower viral load can improve patient outcomes and decrease HIV transmission.
"At 1500 copies, [transmissions] are isolated incidents," she said. "And it seems to go up, obviously, the higher the viral load."
Viral Load by Regimen
While everyone on antiretroviral treatment saw their time with viral loads above 1,500 copies drop during the study period, participants taking non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimens were less likely than those on all other regimens to have viral loads over 1,500 copies. People on protease inhibitor-based regimens spent the most time with higher viral loads, while people on integrase inhibitors saw moderate levels of high viral loads.
"We expected, actually, that more persons may have better outcomes and less time above 1,500 in the integrase inhibitor subset, which is the most modern, contemporary regimen," Buchacz said. "But, in fact, it appeared that persons on NNRTIs did somewhat better."
She said this finding needs more exploration, since the study was based on 5,873 participants at just nine clinics and data abstraction that didn't include information on adherence. It could be, she said, that NNRTI regimens tend to be more durable and perhaps more forgiving of less-than-perfect adherence.
The other surprise, she said, was that people not on treatment at the time of the viral load test sometimes still had viral loads below 1,500 copies. About 4% of participants fit that category.
"There are two subsets of patients there -- either those who are just [antiretroviral] naïve and haven't started therapy yet, and they may present one way," she said. "And then there are patients who are on break."
Data presented earlier at the conference showed that, when people living with HIV stopped taking antiretroviral treatment, it sometimes took up to four weeks for their viral loads to rebound. This, too, should be further studied, she said.
Still, all three CDC presentations could be summed up with a headline that seems to be increasingly common: HIV Outcomes Improve But Disparities Remain.
In Crepaz's study, as in Singh's, young people and African Americans reported worse outcomes. Likewise, women spent more time with viral loads above 1,500 copies than men, and heterosexual women, despite making up only 22% of the study population, spent the most time of any demographic group above 1500 copies.
People were also more likely to spend time above 1,500 copies if they were above that threshold at baseline, if they had a CD4 count of 350 or below at baseline, if they weren't on antiretrovirals at any point in the last 15 years or if they had public insurance such as Medicaid instead of private coverage.
"Time to Intervene"
In other words, the patients that do poorly are, demographically, pretty similar to every patient in the Atlanta clinic of Carlos del Rio, M.D., professor of medicine at Emory University School of Medicine.
"And yet, everyone in my clinic is not above 1,500," he told Buchacz after her presentation. "We need more refined data in order to do interventions. Because otherwise it's impossible to do interventions based on what I see as very broad data that really don't help us on the ground."
Del Rio's comments were seconded by others, who asked whether comprehensive health care services and wrap-around services might be associated with better viral control. (Buchacz didn't have the answer based on her data.)
Erika Samoff, Ph.D., M.P.H., the HIV/STD surveillance unit manager at the North Carolina Department of Health and Human Services, agreed that broad demographic categories -- black, young, female, for instance -- don't tell the whole story. Without more fine-grained analysis and data, it's impossible to know why some young black women do well on treatment and some don't.
"[Broad demographic categories] don't suggest interventions that build empowerment and strength in communities that need to receive better services," she said. Then she added to Buchacz: "And you have medical record data, which is more than a lot of situations. Even if you don't have, say, qualitative, behavioral data, still, by pushing further into it, you may be able to define things. And you may start with a frame of, 'What would be effective and empowering to intervene on?'"
And that's the key, said del Rio, because the disparities remain and remain and remain.
"It's time," he told the room, "to stop describing disparities and start intervening on disparities."
Heather Boerner is a health care journalist based in San Francisco and author of Positively Negative: Love, Pregnancy and Science's Surprising Victory Over HIV.
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