UC San Diego

Persons who inject drugs (PWID) are at risk for adverse health outcomes as a result of their drug use, and the resulting social stigma makes this a difficult population to reach for interventions aimed at reducing morbidity and mortality. During our study of adult PWID aged ≤40 years living in San Diego during 2009 and 2010, we compared three different sampling methods: respondent-driven sampling (RDS), venue-based sampling at one syringe exchange program (SEP), and street-based outreach. We compared demographic, socioeconomic, health, and behavioral factors and tested participants for HIV, hepatitis B virus (HBV), and hepatitis C virus (HCV) and compared across the three methods. Overall, 561 (74.8%) of the targeted 750 PWID were enrolled. Venue-based convenience sampling enrolled 96% (242/250) of the targeted participants, followed closely by street-based outreach with 92% (232/250) recruited. While RDS yielded the fewest recruits, producing only 35% (87/250) of the expected participants, those recruited through RDS were more likely to be female, more racially diverse, and younger.