HIV Pre-Exposure Prophylaxis Awareness and Use Among Men Who Have Sex with Men Only and Men Who Have Sex with Both Men and Women

Gay, bisexual, and other men who have sex with men (MSM) are among those most at risk of HIV in the United States. The estimated lifetime risk of HIV infection among this population is 17%; this increases to 20% and 50% among Hispanic/Latino and African American MSM, respectively. ¹ Further disparities in HIV prevention and care may exist between men who have sex with men only (MSMO) and men who have sex with men and women (MSMW). MSMW, when defined based on past-year bisexual behavior, represent ∼38% of all US MSM and 1% of all US men. ² MSMW face adverse psychosocial conditions—including higher rates of mental illness and substance use, reduced social support, and dual stigma from both same-sex partnering and heterosexual populations—which may function as barriers to health care. ^{3 –5} This may translate to lower uptake of HIV prevention services among MSMW than among MSMO. ^{6 –8}

Pre-exposure prophylaxis (PrEP) is a highly effective HIV prevention intervention that holds significant promise for reducing HIV transmission rates among MSM. ^9,10 Despite its proven efficacy and the high estimated proportion of MSM meeting clinical indications for PrEP, ¹¹ uptake has been suboptimal across the United States, resulting in further disparities among subgroups already facing additional barriers to care, including MSMW. ¹² Characterizing unique risk factors among MSMW is a critical first step in mitigating disparities, promoting prevention strategies, and reducing HIV risk in this population.

We conducted a secondary analysis of data collected during routine clinical care at a sexually transmitted disease (STD) clinic in Rhode Island from January 2013 to December 2018. Data represent unique patients presenting for testing for HIV, syphilis, gonorrhea, and chlamydia. We reviewed data on patients' self-reported demographics, perceived HIV risk, sexual behaviors, and other risk behaviors. If patients had multiple STD clinic visits during the study period, only data from the first visit were included in this analysis. MSMO were men who reported only male oral and anal sex partners in the past 12 months; MSMW reported both male and female oral, anal, or vaginal sex partners in the past 12 months.

Perceived HIV risk was measured using the question, “What is your risk of becoming HIV infected?” (“no risk,” “low risk,” “medium risk,” and “high risk”). PrEP awareness was measured using the question, “Have you heard of taking HIV medications to prevent infections in people who are HIV negative? [Pre-exposure prophylaxis, PrEP].” PrEP use was measured using the question, “Have you ever taken pre-exposure prophylaxis, PrEP?” Both were binary variables (“yes,” “no”).

Bivariate analyses were performed to identify differences in demographic and behavioral characteristics between MSMO and MSMW. Chi-square and Kruskal–Wallis tests were used for categorical and continuous variables, respectively. The primary exposure was bisexual behavior and the primary outcomes were PrEP awareness and PrEP use. Multivariate logistic regression models were conducted to explore the association between bisexual behavior (MSMO vs. MSMW) and PrEP awareness and use. Potential confounding variables were identified using directed acyclic graphs and a priori. All analyses were performed in Stata 15.0 (StataCorp LP, College Station, TX). This retrospective data analysis was approved by the presiding institutional review board.

Of 2153 eligible MSM presenting to the clinic from 2013 through 2018, 1799 (84%) were MSMO and 354 (16%) were MSMW (“a” in Table 1). The median age was 29 years [interquartile range (IQR): 23–43]. The majority were white (70%), non-Hispanic (81%), and insured (55%). Most individuals reported no or low perceived HIV risk (68%), any prior HIV testing (87%), any past-year sex with anonymous partners (61%), no prior injection drug use (97%), and no prior incarceration (96%). The self-reported HIV prevalence was 9% (n = 193). Of 1774 individuals who received an HIV test in the clinic, 2.2% (n = 40) were positive. The prevalence of newly diagnosed gonorrhea (any site—rectal, urethral, or pharyngeal), chlamydia (any site), and syphilis among the study sample was 12%, 11%, and 9%, respectively (data not shown).

Compared with MSMO, MSMW were more likely to be nonwhite and uninsured (“a” in Table 1). Over the preceding 12 months, MSMW were more likely than MSMW to report anonymous sex partners (66.0% vs. 60.0%, p = 0.045), sex while intoxicated (40.6% vs. 34.0%, p = 0.018), sex partners of unknown HIV status (51.4% vs. 44.5%, p = 0.021), and a higher number of sex partners overall [median = 6 (IQR: 3–9) vs. median = 4 (IQR: 2–10), p < 0.001; data not shown]. MSMW were also more likely to report a lifetime history of injection drug use (4.3 vs. 2.4, p = 0.044), incarceration (10.9% vs. 3.1%), and buying or selling sex (12.6% vs. 4.4% and 6.6% vs. 2.5%, respectively). MSMW were less likely to report prior HIV testing (89.5% vs. 76.0%, p < 0.001) and more likely to report prior HIV diagnosis (10.2% vs. 3.1%, p < 0.001) than MSMO.

PrEP awareness and use increased over the study period in both groups (Fig. 1). However, MSMW were less likely to be aware of PrEP (48% vs. 80% among MSMO, p < 0.001) and to have ever used PrEP (4% vs. 9%, p = 0.001) overall. In the multivariate analysis, MSMW were 63% less likely [adjusted odds ratio (aOR): 0.37, 95% confidence interval (CI): 0.28–0.49] to be aware of PrEP compared with MSMO. They were also 54% less likely (aOR: 0.46, 95% CI: 0.25–0.83) than MSMO to have ever used PrEP (“b” in Table 1).

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FIG. 1.

PrEP awareness and use among MSMO and MSMW at an STD clinic, 2013–2018. PrEP, pre-exposure prophylaxis; MSMO, men who have sex with men only; MSMW, men who have sex with men and women; STD, sexually transmitted disease.

This study is among the first to evaluate disparities between MSMW and MSMO in PrEP awareness and uptake, and the first to do so using a real-world clinic-based sample. Both PrEP awareness and uptake were significantly lower among MSMW than among MSMO, an effect that remained after adjusting for age, race, ethnicity, perceived HIV risk, and visit year. MSMW were also less likely than MSMO to report prior HIV testing. These results clearly indicate that some HIV prevention services, even those targeted to MSM broadly, may be less accessible to MSMW. Many MSMW experience a unique form of discrimination on the basis of their bisexual behavior or identity, as well as the absence of the protective phenomenon of gay community support. ^3,5 These factors have been linked to numerous adverse health outcomes among MSMW, ³ including lower PrEP awareness. ⁷ In this way, stigma associated with bisexuality may pose a substantial barrier to HIV prevention behaviors among MSMW.

In addition, a greater proportion of MSMW than MSMO in this sample were uninsured, which may present an additional barrier to engagement in PrEP care. MSMW were also significantly more likely than MSMO to report risk behaviors associated with HIV acquisition, including sex with anonymous partners and partners of unknown HIV status, sex with a higher number of partners, selling or buying sex, injection drug use, and prior incarceration. The higher prevalence of these risk behaviors indicates that PrEP may be especially important among MSMW.

The study has several limitations. HIV risk behaviors and PrEP awareness and use were self-reported. Therefore, we could not exclude the possibility of misclassification and information bias. This secondary data analysis using data from an STD clinic patient population may not be generalizable to MSMW across different settings. However, the clinic-based setting also constitutes a novel aspect of this study. This study supports prior findings of PrEP disparities facing MSMW and provides compelling new evidence for the development of specific HIV prevention interventions in this group.