Harney, B.L.Sacks-Davis, R.Agius, P.van Santen, D.K.Traeger, M.W.Wilkinson, A.L.Asselin, J.Fairley, C.K.Roth, N.Bloch, M.Matthews, G.V.Donovan, B.Guy, R.Stoové, M.Hellard, M.E.Doyle, J.S.Aung, H.L.Baillie, G.Bastian, L.Bateson, D.et al.2025-10-202025-10-202024Open Forum Infectious Diseases, 2024; 11(4):ofae099-1-ofae099-92328-89572328-8957https://hdl.handle.net/2440/147854Background: In Australia, the incidence of hepatitis C virus (HCV) has declined among gay and bisexual men (GBM) with human immunodeficiency virus (HIV) since 2015 and is low among GBM using HIV preexposure prophylaxis (PrEP). However, ongoing HCV testing and treatment remains necessary to sustain this. To assess the potential utility of sexually transmissible infections (STIs) to inform HCV testing among GBM with HIV and GBM using PrEP, we examined the association between bacterial STI diagnoses and subsequent primary HCV infection. Methods: Data were from a national network of 46 clinics participating in the Australian Collaboration for Coordinated Enhanced Sentinel Surveillance. GBM included had ≥1 HCV antibody negative test result and ≥1 subsequent HCV antibody and/or RNA test. Discrete time survival analysis was used to estimate the association between a positive syphilis, rectal chlamydia, and rectal gonorrhea diagnosis in the previous 2 years and a primary HCV diagnosis, defined as a positive HCV antibody or RNA test result. Results: Among 6529 GBM with HIV, 92 (1.4%) had an incident HCV infection. A prior positive syphilis diagnosis was associated with an incident HCV diagnosis (adjusted hazard ratio, 1.99 [95% confidence interval, 1.11–3.58]). Among 13 061 GBM prescribed PrEP, 48 (0.4%) had an incident HCV diagnosis. Prior rectal chlamydia (adjusted hazard ratio, 2.75 [95% confidence interval, 1.42–5.32]) and rectal gonorrhea (2.54 [1.28–5.05]) diagnoses were associated with incident HCV. Conclusions: Diagnoses of bacterial STIs in the past 2 years was associated with HCV incidence. These findings suggest that STIs might be useful for informing HCV testing decisions and guidelines for GBM with HIV and GBM using PrEP.en© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (https://creativecommons. org/licenses/by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.chlamydia; gonorrhea; hepatitis C; HIV; syphilis.Journal article10.1093/ofid/ofae099690450Boyd, M. [0000-0002-6848-3307]