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Evidence of behavioural risk compensation in a cohort study of HIV treatment and transmission in homosexual male serodiscordant couples. Benjamin R Bavinton, Fengyi Jin, Iryna Zablotska , Garrett Prestage, and Andrew E Grulich, for the Opposites Attract Study Group

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  1. Evidence of behavioural risk compensation in a cohort study of HIV treatment and transmission in homosexual male serodiscordant couples Benjamin R Bavinton, Fengyi Jin, Iryna Zablotska, Garrett Prestage, and Andrew E Grulich, for the Opposites Attract Study Group 20th International AIDS Conference (AIDS 2014) 23 July 2014

  2. Background HIV ‘Treatment as Prevention’: HPTN 052 Total seroconversions Total N = 1,763 couples 39 Linked infections Unlinked infections 28 11 Delayed ART Early ART 96% reduction in HIV transmission risk (HR=0.04, 95%CI=0.01-0.27, p<0.001) 27 1 (Cohen et al., 2011, NEJM)

  3. Background HIV ‘Treatment as Prevention’: PARTNER (Rodger et al., 2014, CROI)

  4. Background Behavioural risk compensation • Behavioural risk compensation: Reduction in condom use due to perceived protection from antiretroviral medications. • Behavioural risk compensation has not been evident in clinical studies of antiretroviral-based HIV prevention. • Condom use typically increases in such studies.

  5. Method Study Design • Prospective longitudinal cohort study. • Open enrolment (currently funded until December 2015). • Unit of recruitment is a couple comprising two men in an ongoing sexual relationship where one is HIV-positive and the other HIV-negative at baseline.

  6. Method: Study Sites Bangkok Thai Red Cross AIDS Research Centre Cairns Cairns Sexual Health Centre Rio de Janeiro Instituto de PesquisaClinicaEvandroChagas (IPEC) Brisbane Gladstone Road Medical Centre Melbourne Alfred Hospital Centre Clinic Melbourne Sexual Health Centre Northside Clinic Prahran Market Clinic Sydney Dr Doong’s Surgery East Sydney Doctors Holdsworth House St Vincent’s Hospital (IBAC) Sydney Sexual Health Centre Taylor Square Private Clinic

  7. Method Study Design • Couples attend at least 2 clinic visits per year: • Viral load and CD4 in HIV-positive partners • HIV antibody tests in HIV-negative partners • Both partners complete an online questionnaire at each clinic visit. • Phylogenetic analysis to be conducted at the end of the study.

  8. Method Research Question • Is there evidence of behavioural risk compensation in the Opposites Attract cohort? • Do the HIV-negative partners report more condomless anal sex with their HIV-positive study partner when they perceive their partner to have undetectable viral load? • Are these patterns sustained over time?

  9. Results Enrolments, visits and couple-years • 124 couples enrolled in Australian clinical sites, and 108 (87.1%) had attended at least one follow-up visit. • Number of visits: • Mean: 2.93 visits (SD = 2.03) • Median: 2 visits (range = 1 – 14) • Mean time between visits: 105 days (Median: 90 days) • This analysis includes 129.3 couple-years of follow-up time.

  10. Results Demographics at baseline

  11. Results Relationship characteristics at baseline • Length of relationship: • 69.1% of couples lived together. • 96.0% described each other as ‘partner’, ‘husband’ or ‘boyfriend’. • 48.8% of HIV-negative partners had sex with other partners outside the couple.

  12. Results Antiretroviral therapy and viral load • At baseline, 89.5% of HIV-positive partners were taking ART.

  13. Results Antiretroviral therapy and viral load • At baseline, 89.5% of HIV-positive partners were taking ART. • Viral load pathology results: 75.8 24.2

  14. Results Antiretroviral therapy and viral load • At baseline, 89.5% of HIV-positive partners were taking ART. • Viral load pathology results: 90.0 75.8 24.2 10.0

  15. Results Perceived viral load • 77.4% of HIV-negative partners perceived their HIV-positive partner’s viral load to be undetectable. • Perceptions were mostly in accord with pathology results. • Detectable viral load was overestimated rather than underestimated: • Of the 94 men who perceived the viral load to be undetectable, 2.2% of the partners actually had over 400 copies. • Of the 21 men who perceived the viral load to be detectable, 61.9% of the partners actually had less than 400 copies.

  16. Results Condomless sex (CLS) within the couple • At baseline, total of 66.1% of HIV-negative partners reported ‘any CLS’ with hisHIV-positive partner in the previous 3 months. • These proportions were similar during follow-up. 58.9 37.9 18.6

  17. Results Sex within couples: Total acts of anal sex • Text

  18. Results Sex within couples: Total acts of anal sex • Text

  19. Results Sex within couples: Total acts of anal sex • Text

  20. Results Primary Analysis • What is the association between condomless anal sex and perceived viral load? • Baseline analysis: ‘Any condomless sex’ • Baseline analysis: Number of acts of condomless sex • Longitudinal analysis: ‘Any condomless sex’

  21. Results Baseline: Perceived viral load and ‘Any CLS’ • At baseline, HIV-negative partners were more likely to report CLS with their study partner when the perceived VL was undetectable.OR = 3.5995% CI = 1.49-8.63p-value = 0.004 72.9 42.9

  22. Results Baseline: Perceived viral load and acts of CLS * Wilcoxon Ranksum Test: p < 0.01

  23. Results Across follow-up: Perceived viral load and ‘Any CLS’ Statistical Test Used: Generalised Linear Models (Poisson regression)

  24. Results Across follow-up: Perceived viral load & ‘Any CLS’

  25. Conclusion • Condomless anal sex (CLS) within these homosexual serodiscordant couples is common, and higher than found in other samples of gay men. • CLS is strongly associated with the HIV-negative partner’s perception of his HIV-positive partner’s viral load. • There is evidence of behavioural risk compensation in this cohort, and this pattern of behaviour continues over time.

  26. Conclusion • There may be more evidence for risk compensation relating to HIV-negative partners taking the insertive role in condomless anal sex. • The Opposites Attract Study continues to recruit, and will continue follow-up for a further 18 months.

  27. Acknowledgements All Study Participants Study Investigators: Andrew Grulich, Garrett Prestage, Iryna Zablotska, Fengyi Jin, David A Cooper, Anthony Kelleher, David Wilson, Kersten Koelsch, Christopher Fairley, Kathy Triffitt, Sean Emery, Beatriz Grinsztejn, Nittaya Phanuphak, Benjamin Bavinton Research Assistant: Lara Cassar Site Investigators: David Baker, Mark Bloch, Nicolas Doong, Jennifer Hoy, Anna McNulty, Richard Moore, David Orth, Catherine Pell, Norm Roth, Darren Russell, Ban KiemTee, David Templeton All Recruiting Clinicians Laboratory Partners: Kate Merlin, Doris Chibo, Bertha Fsadni, Shayla Sharmin, Brooke Berry, SandroNazer, TippawanPankam Site Coordinators/Staff: Colette Cashman, Jess Costa, Sian Edwards, Ruth Khalili Friedman, Shruti Gupta, Peta Hamill, Shane Hewitt, Julia Hoffman, PiranunHongchookiat, Vicki Ieroklis, Helen Kent, Helen Lau, Karen McRae, SiripornNonenoy, Elizabeth Odgers, Janine Roney, Egydio Sampaio, Nicky Sharp, Julie Silvers, Kate Sinn, Rachel Woolstencroft, David Youds Community Partners: ACON, VAC, Positive Life NSW, Living Positive Victoria, HIV/AIDS Legal Centre Designers: Danny Adams, James Sheraton

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