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  1. Effects of an HIV/AIDS peer prevention intervention on sexual and injecting risk behaviors among injecting drug users (IDUs) and their risk partners in Thai Nguyen, Vietnam: a randomized controlled trialV.Go, C. Frangakis, N. Le Minh, T. Viet Ha, T. Thi Mo, C. Latkin, T. Sripaipan, W. Davis, P. The Vu, V. Minh Quan1Johns Hopkins Bloomberg School of Public Health2 Thai Nguyen Center for Preventive Medicine

  2. Background • Globally, 30% of new HIV infections occur in injecting drug users (IDUs).1 • HIV-related sexual and injecting risks persist among IDUs. • Peer and network interventions have been shown to be effective at reducing HIV risks among IDUs in different settings.2 1Wodak, 2008 2 Latkin, 2003; Des Jarlais, 1995; Garfein, 2007; Sherman, 2009; Hammett, 2006

  3. HIV epidemic is concentrated among IDUs in Vietnam • Reported # of IDUs: 274,0001 • 75% of HIV infections are among IDUs1 • Prevalence of HIV2 • General population: 0.04% • IDUs: 18% • Marginalized population ________________________ 1The Socialist Republic of Viet Nam , 2010 2Ministry of Health of Vietnam, 2008

  4. Thai Nguyen, Vietnam Thai Nguyen

  5. Trial objective To assess the efficacy of a behavioral, peer network HIV prevention intervention among IDUs in Vietnam on reducing HIV sexual and injecting risk behaviors. • Primary outcomes: • sharing injecting equipment • unprotected sex

  6. Study overview • Two arm randomized controlled trial • Intervention: prevention messaging delivered via existing risk networks • Index members: HIV-negative IDU males 18-45 living in Thai Nguyen Province • Network members: injected drugs and/or had sexual intercourse w/ index in past 3 mos.

  7. Screened at Baseline N=1434 Participants with a Complete Network Group* N=924 Intervention N=465 Control N=459 *Complete Network Group = 1 Index Member + At least 1 Network Member

  8. Recruitment, randomization & data collection • Participants recruited by field workers who were current or former IDUs • Block randomization • Face-to-face interviews at study site & HIV testing and counseling (HTC) per WHO guidelines at baseline, 3, 6, 9 and 12 months

  9. Intervention • Index • Content: Harm reduction, communication strategies, and problem solving • Delivery:2 facilitators leading didactic, interactive discussions and role-playing • Timing: Two-hour sessions weekly for six weeks; booster sessions at 3, 6, and 9 months • Network received intervention content via their index.

  10. Results • Total of 935 participants (index = 419; network = 516) • Overall retention rate: 85% • Among those who dropped out, main reasons included incarceration and moving out of province. • 75% of index participants attended at least 4 out of 6 sessions.

  11. Baseline characteristics of sample (n = 935) Control Intervention Age32.1 31.9 Education Primary 10.1% 10.4% Secondary 42.1% 40.9% High School 47.8% 48.7% Married 32.2% 33.5% Full-time employed58.8% 58.0% Shared needle 3 mos24.2% 27.3% Unprotected sex 62.2% 60.9%

  12. Wald Test for Follow-up Visits: W=5.95, p=0.20

  13. Wald Test for Follow-up Visits: W=12.2, p=0.02

  14. Secondary analyses • Secular trends • Social desirability bias • Contamination • Telescoping • Missing HTC sessions

  15. Exploration of pattern of missed HTC visits and % with unprotected sex. • Among participants who attended baseline and all 4 follow-up assessment visits, no difference between trial arms. • Among those who missed interim visits, the control was more likely to report unprotected sex than the intervention (p<0.01).

  16. Summary of intervention effect • Both arms decreased injecting and sexual risk behaviors after baseline. • At the 12 month visit, the intervention arm was significantly less likely to have unprotected sex as compared to the control arm. • By accounting for missed visits, we found that the intervention had a lasting effect on sexual behaviorscompared to standard HTC.

  17. Implications • Programmatic • Peer network interventions may be effective in facilitating longer term sexual risk behavior change. • HTC may be sufficient for changing injecting risk behaviors. • Future Research • Explore the impact of participating in trial procedures. • Sustainability of effects.

  18. Acknowledgements • Thai Nguyen Center for Preventive Medicine Funding • Fogarty International AIDS Research Program • NIMH# 1 R01 MH64895-01

  19. Summary of secondary analysis • No evidence of selection bias, social desirability, telescoping, secular trends or contamination. • HTC may have reduced injecting behaviors. • HTC may have had a short term impact on sexual behaviors, but the intervention had a longer term impact.

  20. In Vietnam, as in many countries, the HIV epidemic is concentrated among IDUs1 • Estimated # of IDUs: 274,0001 • 75% of HIV infections are among IDUs2 • Prevalence of HIV1 • General population: 0.04% • Sex workers: 3% • MSM: 17% • IDUs: 18% ________________________ 1The Socialist Republic of Viet Nam (2010). The fourth country report on following up the implementation to the declaration of commitment on HIV and AIDS. 2Ministry of Health of Vietnam (2008). The third country report on following up the implementation to the declaration of commitment on HIV and AIDS (reporting period: January 2006-December 2007).

  21. Secondary Analyses • Secular trends- no difference by times of enrollment • Social desirability bias- sero-conversions explained by self-reported risk behaviors • Contamination- HIV discussions did not increase in control arm • Telescoping- Among those who missed a visit, no difference in outcomes prior and after the missed visit. • Missing HTC sessions

  22. Analyses • Intention to treat analysis • Missingness of measures at different visits addressed through multiple imputation • Secondary analyses conducted to explain findings of primary analyses

  23. Effect (I-C) of intervention on needle sharing Indexes (n = 417) Effect (I-C), % (se) 1 2 3 4 5 Wald Test (2-5) 0(2) -1(1) 6 (3) 3(2) 3(2) W = 3.74, p = 0.44 Networks (n = 2*417) Effect (I-C), % (se) 1 2 3 4 5 Wald Test (2-5) 5(3) 0(1) 0(1) 4(2) 1(1) W = 5.95, p = 0.20 *Multiple imputations

  24. Effect (I-C) of intervention on unprotected sex Indexes (n = 417) Effect (I-C), % (se) 1 2 3 4 5 Wald Test (2-5) 4(5) 1(5) 5(6) 9(6) -10(5) W = 10.8, p = .03 Networks (n = 2*417) Effect (I-C), % (se) 1 2 3 4 5 Wald Test (2-5) 2(4) -1(4) 2(4) 3(4) -10(4) W = 12.2, p = 0.02 *Multiple imputations

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