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 trial

V.Go, C. Frangakis, N. Le Minh, T. Viet Ha, T. Thi Mo, C. Latkin, T. Sripaipan, W. Davis, P. The Vu, V. Minh Quan

1Johns Hopkins Bloomberg School of Public Health2 Thai Nguyen Center for Preventive Medicine

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, 20082 Latkin, 2003; Des Jarlais, 1995; Garfein, 2007; Sherman, 2009; Hammett, 2006

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

________________________1 The Socialist Republic of Viet Nam , 20102 Ministry of Health of Vietnam, 2008

Thai Nguyen, Vietnam Thai Nguyen

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

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.

Screened at Baseline

N=1434

Intervention

N=465

Participants with a Complete Network Group*

N=924

Control

N=459

*Complete Network Group = 1 Index Member + At least 1 Network Member

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

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.

Results

1. Total of 935 participants (index = 419; network = 516)

2. Overall retention rate: 85%

3. Among those who dropped out, main reasons included incarceration and moving out of province.

4. 75% of index participants attended at least 4 out of 6 sessions.

Baseline characteristics of sample (n = 935)

ControlIntervention

Age 32.1 31.9

EducationPrimary 10.1% 10.4%Secondary 42.1% 40.9%High School 47.8% 48.7%

Married 32.2% 33.5%

Full-time employed 58.8% 58.0%

Shared needle 3 mos 24.2% 27.3%Unprotected sex 62.2% 60.9%

Baseline 3 Months 6 Months 9 Months 12 Months0tan28a566028

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Needle sharing declined in both arms

ControlIntervention

Study Visit

% W

ho

Sh

ared

Nee

dle

s/S

yrin

ges

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

Baseline 3 Months 6 Months 9 Months 12 Months0tan28a566028

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Unprotected sex decreased significantly more in the intervention arm

ControlIntervention

Study Visit

% W

ho

Had

Un

pro

tect

ed S

ex

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

Secondary analyses

• Secular trends• Social desirability bias• Contamination• Telescoping• Missing HTC sessions

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).

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 behaviors compared to standard HTC.

Implications

• ProgrammaticPeer network interventions may be effective in

facilitating longer term sexual risk behavior change.

HTC may be sufficient for changing injecting risk behaviors.

• Future ResearchExplore the impact of participating in trial

procedures. Sustainability of effects.

Acknowledgements

Thai Nguyen Center for Preventive Medicine

Funding Fogarty International AIDS Research Program NIMH# 1 R01 MH64895-01

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.

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%

________________________1 The Socialist Republic of Viet Nam (2010). The fourth country report on following up the implementation to the declaration of commitment on HIV and AIDS.2 Ministry of Health of Vietnam (2008). The third country report on following up the implementation to thedeclaration of commitment on HIV and AIDS (reporting period: January 2006-December 2007).

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

Analyses

• Intention to treat analysis

• Missingness of measures at different visits addressed through multiple imputation

• Secondary analyses conducted to explain findings of primary analyses

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

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