Characterizing A Subset of MSM Who Also Have Intercourse with Cisgender Women in Lima, Peru: A Cross-Sectional Secondary Data Analysis with a Prospective Cohort Component

Abstract

Background: MSM are disproportionately affected by HIV in Lima, Peru. A subset of MSM, men who have sex with men and women (MSMW), have unique sexual behavior and demographic characteristics that are distinct from MSM overall. Due to their bisexual behavior, MSMW may play an important role in facilitating HIV transmission to cisgender women. Since an initial study done in 2002, there have been limited reports looking at this subset of MSM in Peru. The purpose of this study is to characterize demographics and sexual behavior of MSMW compared to men who have sex with men only (MSMO), compare MSMW’s sexual behavior with male versus cisgender female partners, compare sexual behavior with male partners between MSMW and MSMO, and compare HIV incidence between the two groups. Methods: Data for these analyses were collected as part of the larger Sabes study, a treatment as prevention study in Lima, Peru, conducted between 2013 to 2017. We identified participants based on a question about sexual behavior with cisgender women in the last 3 months. All participants were tested for HIV at baseline. Chi-square, Fisher exact tests, and t-tests were used to draw conclusions about differences in characteristics between MSMO and MSMW subgroups as well as differences in sexual behavior with male partners between the two groups. We used logistic regression with clustering on each MSMW to compare partnerships with cisgender female vs cisgender male partners. Finally, we calculated HIV incidence among MSMO and MSMW. Results: Compared to MSMO, MSMW had significantly lower levels of education and were more likely to self-identify as bisexual. A higher proportion reported insertive sexual role. Most (93%) MSMW reported vaginal sex in the last three months; 78% reported not using a condom. Among MSMW who reported anal sex with their female partners (26%), 67% reported not using a condom. There was no statistically significant difference in MSMW’s partner type (stable vs. not) or location (e.g. home vs. public location such as hourly hotel) of sexual intercourse between male and female partners. MSMW were more likely to have anal insertive sex and half as likely to have anal receptive sex with male partners compared to MSMO. MSMW were twice as likely to indicate high risk for alcohol abuse and were more likely to engage in transactional sex. HIV incidence in MSMO did not differ significantly from that in MSMW (11.9 vs. 8.8/100 person-years) (Rate ratio:1.3, 95% CI: 0.9-2.1). Conclusion: There are distinct sociodemographic factors and sexual behaviors among MSMW compared to MSMO. While some of these may signal lower HIV risk (e.g. insertive sex role, lower HIV prevalence among women), others likely carry higher HIV risk (e.g. low condom use, alcohol abuse, transactional sex). Understanding these distinct differences between the two populations provides insight into possible intervention strategies and gaps in current practices.