Are Current PrEP Guidelines and HIV Risk-Screening Tools Accurate Enough?
John Schneider, M.D., M.P.H. (Credit: Terri Wilder)
Identification of clients at highest risk of acquiring human immunodeficiency virus (HIV) is a critical component to PrEP implementation. CDC published clinical practice guidelines for identifying individuals as PrEP candidates in 2014 and developed a risk-screening tool:
One of the key components of PrEP (pre-exposure prophylaxis) rollout is identifying those who are at highest risk of HIV. The CDC (U.S. Centers for Disease Control and Prevention) has clinical guidelines for identifying PrEP candidates and developed a risk-screening tool. One study examined how accurate these current guidelines and risk-screening tools are among a group of young Black men who have sex with men. Terri Wilder, M.S.W., spoke with study author John Schneider, M.D., M.P.H., at CROI 2017, in Seattle.
Terri Wilder: Can you take our readers through your study, telling us about the background, objective methods, your analysis and, of course, your conclusions?
John Schneider, M.D., M.P.H.: Sure. We started a cohort study in 2012 that was focused on young black gay and bisexual men in Chicago. We started in 2012 because that's when pre-exposure prophylaxis [PrEP] really started being implemented. We followed this cohort over time. We were really interested in how the different guidelines -- the Centers for Disease Control and Prevention [CDC] guidelines, the HIRI Risk Index guidelines and Gilead indications -- would predict whether someone seroconverted or not. And so, [cohort members] were followed over time. They were asked a bunch of questions relative to the guidelines. This was a sample of 612 individuals at baseline.
What we found was very interesting. First of all, all of the traditional risk factors -- you know, things like having an anal/rectal sexually transmitted infection, having a sexual relationship with an HIV-positive male partner -- all these sorts of things did not predict seroconversion. The only thing that predicted seroconversion in this cohort was having a partner 10 or more years older than you.
The CDC clinical practice guidelines missed about half of the seroconversions. There were 33 seroconversions, and half of those people would not have been eligible for PrEP according to the CDC guidelines.
Now, you know, more of them were eligible with the HIRI guidelines and the Gilead guidelines, but then those guidelines also identified more people that would not seroconvert, so the specificity would go down. We found that the HIRI guidelines was probably the best, but it still had limitations.
In some, the implications of this are really that if a general provider who doesn't do a lot of PrEP care, or doesn't know about the epidemic, opens up some guidelines, they may have different implications for the clients that they're serving. They may miss some who need it, and they may give it to some who don't need it. We might want to think about guidelines that are not based on risk behaviors but more on network prevalence of HIV.
TW: Can you talk a little bit more about the HIRI Risk Index that may have missed a little something? Is there something that maybe needed to be added to that from your analysis?
JS: I think it did really well. The reason why it did well is because it really, for younger guys, it really increased the index. The age piece was important. In young black gay and bisexual men being 16 to 29 is an important age group. That wasn't included in some of the other indices.
What can be added to it? It's doing pretty good at capturing who, at predicting who, would have a seroconversion if they weren't on PrEP. Not as good as Gilead, but Gilead had very permissive guidelines. For the 15% that were missed, I can't tell you off the top of my head what would capture them. It's clearly not any of the classic variables that people look at.
TW: When you think about guidelines, there's the CDC guidelines, there are some states that have their own guidelines -- for example, the New York State Department of Health AIDS Institute has its own PrEP guidance -- if we're going to get to a place where we're offering and getting folks on PrEP who really need to be on it, what do you think would be a strategy to think about, in addition to guidelines or guidance?
JS: Well, I think a lot of good public health messaging campaigns, whether that's online, whether that's traditional posters, billboards; that sort of thing. In Chicago, we have the PrEP for Love campaign; it's a sex-positive campaign. People can call in and learn more about PrEP. We basically start most people on PrEP and then decide later on whether they should stop PrEP.
Not enough people are talking about: How do you stop PrEP? But it's hard for clinicians. The question I think we have to face is whether this is going to be something that every doc in their clinic is going to offer, or whether people have to have specialized training and understanding about what it means to be a good PrEP provider.
Its intent was to be in every primary care setting. I think that's noble. But in actuality it takes a lot of experience to work with the populations that need it most.
TW: In terms of clinical education, in terms of training medical providers -- whether an M.D., a nurse practitioner, a physician assistant -- I wonder if you can speak to whether there is room for knowing your epidemic as part of a strategy to identifying folks for PrEP?
JS: Yeah. It's knowing your epidemic. But you could be in a specific geographic location and have people that come from outside of that geographic location. And even within the geographic location, there are just so many strata of people -- by race, age, ethnicity -- that it's hard to pull up an AIDS view map and say, well, this neighborhood has a lot of HIV, so we should give it.
Sure. It's crude. So, you could follow that. But it's not -- it's going to still miss some, and it's still going to give people PrEP who don't need it.
TW: In terms of social networking, looking at that, can you speak to that, as well?
JS: Yeah. I'm obsessed with networks. Yeah.
TW: OK. Tell me about your obsession.
JS: Networks drive everything. Sure, there's behaviors; but the real drivers of HIV are network phenomena. So, we don't know enough about who we're exposed to. Classically, in this community, for example, young black gay and bisexual men have fewer sex partners. They use drugs less than their white men who have sex with men counterparts. Yet, they have higher rates of HIV. And so it's a network phenomenon. It's the surrounding seroprevalence in the patterns of mixing.
If we can have network data, which is hard to get, then this is easy. In fact, in the Gilead recommendations, all these risk factors were in the network members. You know, if your network member has gone to jail, if your network member is using a lot of drugs -- that's more predictive of one's own probability of getting infected. So, you know, for whatever that's worth. It's just hard to get. That's why people use these proxies, such as, behavioral -- you know, "Do you use condoms?" "How many partners do you have?" Things like that.
TW: Great. Very interesting. Thank you so much.
This transcript has been lightly edited for clarity.
Terri L. Wilder, M.S.W., is a director of HIV/AIDS education and training in New York City.