In this prospective and multicentric study of HIV-positive MSM who were followed-up in HIV clinics in Île-de-France, we highlighted that 1 out of 10 HIV-positive MSM was also coinfected with HCV. This prevalence is much higher than the estimated prevalence found in HIV-positive MSM in the cross-sectional survey PREVAGAY in 2015 in France (3%) , but lower than that reported in HIV-positive MSM in the Dat’AIDS cohort in 2016 in France . However this lower prevalence in the French PREVAGAY study might due to the use of DBS for HCV antibodies detection, which could lead to an underestimation of HCV prevalence [32, 33], but also to the younger age of the participants. Nevertheless the prevalence of HCV infection found remains comparable to those reported among HIV-positive MSM in Amsterdam (11.8%)  and in a meta-analysis of international observational studies among HIV-infected MSM (8.1%) .
The main result of the study is the identification of two main modifiable risk factors (in terms of strength of association), i.e. recent GHB or amphetamine use. In the univariate analysis amphetamine users exhibit the highest risk (8-fold) of HCV acquisition. Due to the confounding and overlapping of some risk factors, this association decreases in the multivariate analysis though it remains the strongest association with the outcome in the final model.
Comparable findings were reported in Montréal  and in Thailand . In fact, GHB or stimulants are used during sex in MSM to decrease inhibition, which favor risky behaviors for HCV acquisition such as syringes or needles exchange, increasing number of sexual partners and condomless receptive anal intercourse. Whatever the administration route (rectally, orally or intra-nasally), these substances may favor contact with partner or fellow user’s secretions or blood, where HCV could replicate . It was also well documented that HIV-positive MSM who reported amphetamine-type substance use reported also group sex, associated with risky behaviors [17, 36]. This probably explains why this variable in the model decreases the association between amphetamine use and HCV acquisition. The association with group sex is in line with our study; in which reporting risk practices during group sex was a strong predictor of HCV seropositivity among HIV-positive MSM. Group sex participation might be associated with other risk sexual practices such as unprotected fisting (without gloves), sharing sex toys or condomless receptive anal sex that could cause mucosal tissue traumatism and rectal bleeding, facilitating thus HCV infection .
Our findings showed that HIV-positive MSM who reported seeking sensation, including sexual sensation were more likely to have HCV infection, particularly those who declared: “My sexual partners must think that I’m a risk taker”. It was also demonstrated that in sexual minority individuals high seeking sensation might encourage them to be engaged in intentional unsafe sex most often mediated by alcohol use or drug use before sex [38, 39], with an increased risk of HCV infection.
Our study also showed that HIV-positive MSM with active syphilis infection or history of anal proctitis were more likely to be infected with HCV. Similar to previous studies [17, 40, 41], active the presence syphilis infection with an anorectal or oral chancre and other ulcerative STI, including lymphogranuloma venereum, might increase the risk of transmission HCV infection among HIV-positive MSM, as these lesions could serve as a portal of entry for HCV .
Our findings suggested the high burden of HCV and HIV coinfection among MSM in Île-de-France, hence the need to strengthen interventions for micro-elimination but also the implementation of harm reduction strategies (especially among drug users) for HCV eradication among this core group. Since 2016, universal access to DAA announced by the French Ministry of Health , access to DAA-based treatment for HCV infection has been extended to all patients with active HCV-infection, regardless of their profile or the stage of liver disease. This may greatly change the course HCV epidemic among HIV-positive MSM. In the context of high rate of HCV screening, modelling data demonstrated that by increasing treatment coverage, DAA could favor HCV infection elimination in MSM, even in the most highest group, including intra-venous drug users . Recently, the European treatment Network for HIV, Hepatitis and Global Infectious Diseases (NEAT-ID) consensus panel recommend immediate HCV treatment after diagnosis in HIV-positive MSM in order to prevent HCV transmission . An encouraging study conducted in the French large Dat’AIDS cohort of HIV-positive patients has shown that the majority (82%) of patients with HCV and HIV coinfection including MSM were treated and cured for HCV infection . Given the high prevalence and persistence of HCV infection, HIV-positive MSM are considered as one of main targets and a priority population for of HCV micro-elimination.
Furthermore, in HIV-positive MSM remained at increased risk of HCV reinfection, due to their engagement in high-risk behaviors, particularly in those who reported intravenous drug use . Harm reduction strategies, assuming needle and syringe provision and supervised drug injection or opioid substitution treatment, may be effective and promote safe drug injecting practices . In a harm-reduction program implemented in Australia for methamphetamine users MSM, authors found significant change in participants’ behaviors in terms of sexual risk behavior and high risk drug use behavior, including reductions in methamphetamine use post intervention . Therefore, the scale-up of screening for HCV, HCV treatment and prevention interventions, harm reduction interventions, including safe behaviors, should be needed to minimize the risk of HCV re-infection in this vulnerable group.
Our study has some limitations. This study was conducted among HIV-positive MSM followed up in HIV clinics in Île-de-France. Therefore, the sample may not be representative of the whole country. In addition, it was likely to include a high proportion of HIV-positive MSM with better prevention behaviors or HIV-positive MSM less infected with HCV. Some behavioral data, including sexual behavior and drug use based on self-reports may have been affected by social desirability bias (underreporting of drug use or history of drug use, for example). This study did not assess HCV reinfections in HIV-positive MSM and that could contribute to a misclassification of participants in high groups.