1. Reductions in injection-related risk behaviors
following successful virologic suppression
among IDUs treated with HAART
Ryan P. Westergaard, MD, MPH
Department of Medicine
University of Wisconsin School of Medicine & Public Health

2. Disclosures
No relevant financial interests to disclose
ref

3. Objectives
1. To review the utilization of HIV RNA testing
for epidemiologic research
2. To illustrate an example of using serial HIV
RNA measurements to the association
between HIV viral suppression and risk
behavior change
ref

4. HIV-1 RNA
Watts JM, Nature 2009; 460:711-16.

5. HIV RNA predicts infectiousness
Quinn TC, NEJM. 2000; 342:921-9

6. Suppression of HIV RNA prevents infection
Cohen M. IAS 2011; Rome. Abstract MOAX0102

7. Community Viral Load (cVL)
• Aggregate measure of HIV RNA (e.g. mean, total, max)
for a defined geographic or demographic population
• General Principle:
Increased HAART uptake  reduced cVL  lower HIV incidence
Wood E et al. BMJ. 2009; 338:1649

8. Community Viral Load (cont.)
Das M et al. PLoS ONE. 2010; 5:e11065

9. AIDS Linked to the IntraVenous Experience
The ALIVE Study
Community-based, prospective
cohort study of injection drug
users in Baltimore, MD
~4,500 IDUs recruited since
1988
25% HIV seroprevalence
Semi-annual follow-up with
extensive data collection:
- HIV RNA
- CD4+ cell count
- Risk behavior screens

10. Community viral load in ALIVE
Kirk GD, CROI 2011; Boston. Abstract #484

11. Reductions in injection-related risk behaviors
following successful virologic suppression
among IDUs treated with HAART
Analysis of longitudinal HIV RNA and risk behavior data from ALIVE

12. Research question
Is effective HAART associated with changes in the
frequency of HIV transmission risk behaviors?
• Behavioral risk compensation a common concern related to HIV
prevention interventions (HIV vaccine trials, medical circumcision)
• Is this a concern relevant to “treatment as prevention”

13. Research design
Risk behavior assessment:
• Any injection drug use
• Needle sharing Assessed any occurrence of
• “Shooting gallery” use behavior in preceding 6 mo.
• Number of sex partners
• STI diagnosis
Main exposure of interest:
Receipt of HAART and undetectable HIV RNA at the time of each
semiannual study visit.
Potential Confounders:
• Age
• CD4+ cell count (disease stage)
• Gender

14. Analysis
• Compared self-reported engagement in 5 risk behaviors
at study visits where HIV RNA <400/mL and visits when
HIV RNA > 400/mL
• Logistic regression with generalized estimating
equations (GEE) used to adjust for intra-person
correlation due to repeated measurements

15. Results
• 767 IDUs accounted for 7,278 visits when HIV RNA was measured
• 67% male
• 94% African-American
• 61% HAART-experienced
% reporting behavior (6m)
Risk behavior p-value
HIV RNA < 400 HIV RNA Elevated
Any IDU 25.7 47.4 <0.001
Needle sharing 13.2 25.2 <0.001
Shooting gallery 2.3 4.8 <0.001
STI 3.3 2.5 0.046
Number of sex NS NS NS
partners
• Multivariate model: adjusted OR for needle sharing = 1.25 (p<0.001)
i.e. Odds of NS increase by 25% for every increase log HIV RNA

16. Conclusions
• No evidence of injection-related behavioral risk
compensation for IDUs successfully treated with HAART
• Conversely, all 3 measures of injection risk behavior
were significantly lower when HIV RNA <400 copies/mL
• STIs more frequent when HIV RNA suppressed, but
association not significant in adjusted model

17. Limitations
• Self-reported risk behaviors may not accurately reflect
transmission probability
• Recall bias
• Socially-desirable reporting
• Undiagnosed or asymptomatic STIs not captured
• External generalizability may be limited
• Older, well-studied cohort of mostly Black IDU