Correlates of HIV Infection Among Transfemales, San Francisco, 2010: Results From a Respondent-Driven Sampling Study

Objectives. We evaluated the use of respondent-driven sampling (RDS) among a high-risk population of transfemales. We also obtained up-to-date epidemiological data on HIV infection and related correlates among this population. Methods. We evaluated the utility of RDS in recruiting a sample of 314 transfemales in San Francisco, California, from August to December 2010 by examining patterns of recruitment and assessing network sizes and equilibrium. We used RDS weights to conduct bivariate and multivariate analyses of correlates of HIV infection. Results. The sample had moderate homophily and reached equilibrium at the eighth wave of recruitment. Weighted HIV prevalence among transfemales was 39.5%. Being a transfemale of color, using injection drugs, and having low educational attainment were independently associated with HIV infection and having a high number of sexual partners and identifying as female were not. Conclusions. RDS performed well and allowed for analyses that are generalizable to the population from which the sample was drawn. Transfemales in San Francisco are disproportionately affected by HIV compared with all other groups except men who have sex with men who also inject drugs.