Reaching black men who have sex with men: a comparison between respondent-driven sampling and time-location sampling.

OBJECTIVES: The authors explored whether respondent-driven sampling (RDS) can generate a more diverse sample of black men who have sex with men (MSM) than time-location sampling (TLS) by comparing sample characteristics accrued by each method in two independent studies.
METHODS: The first study exclusively recruited black MSM through RDS (N=256), while the second recruited MSM through TLS including a subsample of black MSM (N=69). Crude and adjusted point estimates and 95% CIs were calculated for socio-demographic and behavioural characteristics, HIV prevalence and prevalence of unrecognised infections, and were compared using the Z-test.
RESULTS: The samples differed significantly regarding all socio-demographic and some behavioural characteristics. Compared with TLS, RDS estimated higher proportions of older, less educated, poorer, currently homeless and self-identified bisexual black MSM. Participants in RDS were less likely to have a main partner, had fewer male partners, were more likely to have a female partner and have both male and female partners, and reported greater methamphetamine, crack and heroin use. Prevalence of HIV and unrecognised infections were slightly higher among RDS participants.
CONCLUSIONS: The RDS sample comprised black MSM who were more diverse with respect to socio-demographic characteristics and may also be at higher risk for HIV. Thus, RDS has advantages in reaching higher risk black MSM who are most hidden from intervention research and service delivery. Future studies of black MSM using RDS could use steering strategies to recruit younger participants and other subgroups of greatest interest to public health and prevention.