1. The Effectiveness of Respondent-Driven Sampling to Recruit Minority and Hard-to-Reach MSM for STD/HIV Behavioral Surveillance

2. Collaborators
Carey V. Johnson1, Matthew J. Mimiaga1, 2, Sari L. Reisner1,
Ashley M. Tetu1, 3, Kevin Cranston4, David S. Novak4, and
Kenneth H. Mayer1, 5
1The Fenway Institute, Fenway Community Health, Boston, MA
2Harvard Medical School/Massachusetts General Hospital, Boston, MA
3Boston University, School of Public Health, Boston, MA
4The Massachusetts Department of Public Health, Boston, MA
5Brown University, School of Medicine/Miriam Hospital, Providence, RI

3. Introduction Objectives Overview of Respondent-Driven Sampling (RDS)
Study findings
RDS strengths, limitations & applications
Questions & discussion

4. Objectives
The present study assessed the ability of RDS to recruit a diverse population of men who have sex with men (MSM) in the Boston area
By the end of the presentation, participants will be able to describe RDS and its implications for accessing difficult-to-reach populations for STD/HIV surveillance and prevention interventions

5. Background
MSM represent an increasingly disproportionate share of new cases of STDs, including drug-resistant gonorrhea and infectious syphilis
MSM constitute a hard-to-reach population for STD/HIV surveillance because the frequency of behaviors are rare and often stigmatized, illegal and/or forbidden
CDC, 2006

6. Respondent-Driven Sampling
RDS is a relatively new chain-referral sampling method that utilizes the social networks of participants themselves to engage other members of the target population, using the dual incentives of peer-based recruitment and financial compensation*
RDS has been applied to injection drug users, sex workers and MSM all over the world
*Heckathorn, 1997, 2002

7. Respondent-Driven Sampling
RDS can potentially provide unbiased estimates of the underlying population of interest if certain conditions are met
These conditions relate to the
target population
recruitment methods
data analysis

8. RDS: Target Population
Target population should contain members
willing and able to recruit others
there should be reciprocal social ties sufficient to reach all members and to sustain recruitment

9. RDS: Recruitment Methods
Sampling begins with enrollment of initial recruiters known as “seeds”
Seeds must be willing, able and sufficiently motivated to recruit other members of their social network from the target population
Examples of recruits can be friends, relatives, or sexual partners, depending on the pre-determined eligibility criteria of the population of interest

10. RDS: Recruitment Methods
Upon completion of study participation (including compensation), each seed is then given a set number of recruitment coupons (usually 3-4) and encouraged to recruit others from his social network
Seeds are then compensated for each participant they successfully recruit into the study
Subsequent recruits (“waves”) are likewise compensated and encouraged to recruit additional waves until the desired sample size is reached

11. RDS: Recruitment Methods
Given sufficient numbers of seeds, recruitment rates, and recruitment waves, the sample will eventually attain ‘equilibrium’, a composition mix independent of the seeds’ characteristics
Equilibrium provides an unbiased sample generalizable to the population of interest
Heckathorn, 1997, 2002

12. RDS: Data Analysis
RDS Analysis Tool (RDSAT) is free, downloadable software from
RDSAT can provide population proportions, average personal network sizes, measures of association (homophily) among group members, and statistically significant measures (standard error, confidence intervals) for population estimates
Seeds represent a biased sample and should be removed from any analysis to derive population estimates

13. RDS: Data Analysis
In addition to variables of interest, RDS analysis requires the collection and management of 3 sets of data per participant:
personal network size
respondent’s coupon number
respondent’s recruiting coupon numbers
2008

14. Study Overview
Between March 2006-May 2007, 126 Boston MSM were recruited using RDS. Recruitment was terminated prior to equilibrium to exploit in-group recruitment tendencies, optimizing sample diversity.
All participants completed a quantitative survey to assess STD/HIV risk behaviors, STD screening frequency, and knowledge and acceptability of Partner Notification services

15. Study Overview Participants were eligible if they were
18 years of age or older
Massachusetts resident
MSM
Seeds were recruited from FCH if they had recently presented for STD screening due to symptoms or high-risk behavior, or had recently received an HIV diagnosis

16. Study Findings Seeds (n=10) Seed Recruits (n=116)
Overall Sample (n=126)
Age: Mean (SD)
41 (10)
43 (9)
43 (8)
HIV status
70% HIV+
30% HIV-
53% HIV+
3% Unknown
54% HIV+
Race
60% White
40% Black/AA
44% White
46% Black
6% AI/AN
45% White
45% Black
Latino/Hispanic 0%
12%
11%
Annual income <$12,000
30%
45%
44%
No regular place to live
20%
22%
21%
Sexual self-identity
80% Gay
20% Bisexual
63% Gay
31% Bisexual
3% Heterosexual
3% Other
64% Gay
30% Bisexual
2% Heterosexual
Not “out” as MSM
13%*
12%*
* 87% of whom were non-white

17. Study Findings
Between seeds and subsequent waves, no significant differences were found with respect to
Age
HIV status
Race
Income
Education
Sexual self-identity

18. Study Findings
Seeds were more likely to disclose their MSM attraction/behavior to partners (OR = 4.33, P < 0.05) and to their health care providers (OR = 6.98,
P < 0.01) compared to waves
Seeds were more likely to be privately insured, later waves (>6) were more likely to be publicly insured
(P < 0.01)
Non-white participants were more likely to have
< high school education and to earn < $12,000 annually relative to white participants (P < 0.05)

19. Discussion
Traditional FCH recruitment methods yield samples comprised of 15%-30% racial/ethnic minority MSM
This study provides evidence that RDS can effectively engage hard-to-reach MSM, including MSM who are non-white, low-income and/or who have not disclosed their MSM orientation to others
This has important implications for engaging ethnic/racial minority and other MSM in STD/HIV surveillance and prevention interventions

20. Thank You! cjohnson@fenwayhealth.org