There’s more data for trans people with HIV than any other disease — but it’s still flawed

Transgender people are at higher-than-average risk of contracting HIV. And yet, when epidemiologist Diana Tordoff set out to analyze how transmission of the virus might change in the U.S. over the next 10 years with increased testing and preventative PrEP medication, she found there wasn’t enough existing data on trans and nonbinary people to answer the question for those populations.

“At the bare minimum, you need prevalence data,” Tordoff said: How many trans men in the U.S. have HIV? How many nonbinary people? The Centers for Disease Control has recently published some data on HIV prevalence among trans people based on public health surveillance data, but gender identity data is not collected consistently across local jurisdictions. This means people are almost certainly being misclassified as the data is aggregated nationally, Tordoff said.

There’s a dearth of data on LGBTQ+ people as a whole, which means there often aren’t definitive answers to basic questions — a shortcoming with wide-reaching implications for building the mathematical models intended to help policymakers develop approaches to preventing and treating HIV.

“Excluding any population, especially trans folks, from these models that have a particularly strong influence on policy is problematic,” said Tordoff, a postdoctoral scholar at The PRIDE Study at Stanford University.

That’s because, in a mathematical model, if you don’t explicitly include a group, it’s as if they don’t exist — making it impossible to look at the potential impact of a given policy or program on that group.

Historically, there’s been more of a focus on trans people in HIV research than in any other area of health care, but the lack of inclusive models demonstrate that it’s still not enough. Researchers say that addressing the underlying gaps in data would not only help to improve HIV policy, but could improve health care for queer people as a whole.

“There are consequences to not having the data, but not having the data is also a consequence of not valuing the lives of trans people,” said Brian Minalga, one of Tordoff’s co-authors and the deputy director of the Office of HIV/AIDS Network Coordination at Fred Hutchinson Cancer Research Center.

‘The research wasn’t designed with trans people in mind’

Mathematical models are like simulations run on a computer. Researchers build the framework of a real-world situation from the ground up, then fill that frame with real-world data to see how it might play out. The goal is to set forth what is likely to happen in a certain population when including factors that are relevant to how a disease spreads, or how an intervention might prevent that spread. For HIV, this includes patterns of sexual behavior, condom and PrEP usage, and more.

There are likely hundreds of mathematical models focused on HIV, dozens of which are most commonly used. But only seven models include trans people at all, according to Tordoff, who co-authored a paper on the barriers to developing more inclusive models in the Journal of the International AIDS Society in June. One of the seven, the AIDS Epidemic Model 2023, is used by 13 Asian countries to estimate national transmission trends. But the others are smaller and less adaptable equations. Several were done in Peru, including one analyzing how PrEP might impact HIV transmission among men who have sex with men and trans women in Lima.

But even among these more inclusive models, there are two key problems, Tordoff and her co-authors wrote.

First, the available models only include trans women — none look at the impact of HIV on trans men or nonbinary people.

“We have an enormous amount of the same kind of information,” said Tonia Poteat, a professor at UNC Gillings School of Public Health who focuses on HIV and trans populations. And the data on trans women is still inconsistent — a systematic review of research on HIV prevalence among transgender people found that most studies used convenience or “snowball” sampling methods (where participants are asked to recruit others), which could bias estimates. That review estimated HIV prevalence among trans women to be 18.8%. But the U.S. Transgender Population Health survey estimates prevalence to be 6.5% among trans women.

The second problem is that the models assume that trans women partner exclusively with cisgender men. “Which you just know is not true,” Tordoff said.

There’s evidence that increased access to gender-affirming care like hormones can increase adherence to other types of disease prevention among trans people, including HIV prevention measures like taking PrEP and getting STI-tested. Tordoff would love to see a model that estimates how increasing access to gender-affirming care for trans people affects HIV transmission — but without data, it isn’t possible.

Researchers and advocates have long called for the inclusion of SOGIE data — or sexual orientation, gender identity and expression data — across electronic health records, public databases, registries, and clinical trials to get a better understanding of these marginalized populations.

Many researchers who focus on issues related to LGBTQ+ health got their start in HIV/AIDS work. In those early days, researchers spent a lot of time simply trying to convince people that trans women were not the same as men who have sex with men, Poteat said, which may be partly why there’s so much focus on that population in HIV research today.

In a separate study, Minalga looked at 41 milestone HIV clinical trials between 1991 and 2023. They found that out of more than 170,000 total participants, less than 1% were identified as part of the trans community, and 94% of those were trans women.

“Trans people are definitely in these studies. They’re just not recognized as such, and the research wasn’t designed with trans people in mind,” Minalga said, noting that the first major HIV prevention study to use the word “transgender” at all was published in 2005. “Even though trans people are participating in clinical research and giving our biospecimens, our blood, our tissues, our time — when those data get analyzed, published, and presented, and then inform clinical practice, they don’t make it back to us.”

If the lack of data on trans people is harmful for HIV research and policy development, the consequences are amplified even further for areas of health that haven’t been so publicly tied to LGBTQ+ populations, Tordoff said. Clinicians often don’t have extensive data on how certain interventions or treatments work for trans patients. This means they need to extrapolate from data on cisgender people, but not every physician is comfortable doing that.

The push for better data collection on gender identity

Change could be coming. In November 2023, the Centers for Medicare and Medicaid Services introduced optional questions on SOGIE data for state Medicaid programs to collect from applicants. The agency recommends collecting information on sex assigned at birth, gender identity, and sexual orientation. While data from CMS wouldn’t be nationally representative, self-reported SOGIE data has never been collected on such a large scale, according to Nathaniel Tran, an assistant professor at the University of Illinois at Chicago School of Public Health who wrote in JAMA about the potential impact of the move.

Few states currently collect this data on Medicaid applications, and no states collect all SOGIE information in the same way. Tran hopes the National Association of Medicaid Directors, a nonpartisan group of state program directors, will be able to streamline data collection.

“This is a lower-hanging fruit,” said Tran.

At the same time, legislation restricting gender-affirming care continues to spread across the country, which could stifle efforts to collect more meaningful health data on queer populations.

It makes sense, Tran said, that LGBTQ+ people who live in states restricting access to gender-affirming care would not trust the state to protect their data. “That’s a very pragmatic tension,” they said.

But Tran believes that most clinicians and researchers don’t have bad intentions, but rather have never had the opportunity to learn about LGBTQ+ populations in the first place. “You caught me on a very optimistic day,” they said.

In the meantime, researchers focused on LGBTQ+ populations are left to manage their own work balancing the need for even better data on trans people with HIV, and the enormous gaps for data on the trans population in every other health area.

Poteat, whose research often focuses on HIV and trans people, says that trans people participating in research are also frustrated by the way they are considered. People are tired of being asked personal questions about their sex life and then not seeing themselves or their needs reflected in the results.

“Part of my passion for HIV is because of all that it represents and highlights the structural challenges in our society,” Poteat said. “It reminds us of the consequences of homophobia and transphobia and racism.”