BACKGROUND: Most studies on hepatitis C virus (HCV)/HIV co-infection do not account for the order and duration of these two infections. We aimed to assess the effect of incident HCV infection, and its timing relative to HIV seroconversion (HIVsc) in HIV-positive men who have sex with men (MSM) on their subsequent CD4 T-cell count (CD4) and HIV-RNA viral load (VL) trajectories.METHODS: We included MSM with well-estimated dates of HIVsc from 17 cohorts within the CASCADE Collaboration. HCV co-infected MSM were matched to as many HIV mono-infected MSM as possible by HIV-infection duration and cART use. We used multilevel random-effects models stratified by cART use to assess differences in CD4 and VL trajectories by HCV co-infection status.FINDINGS: We matched 214 (ART-naïve) and 147 (on cART) HCV co-infected MSM to 5,384 and 3,954 respectively matched controls. The timing of HCVsc relative to HIVsc had no demonstrable effect on VL or CD4 trajectories. In the first 2-3 years following HCVsc CD4 counts were lower among HCV co-infected MSM, but became comparable to HIV mono-infected MSM thereafter. In ART-naïve MSM, during the first two years after HCVsc, VL levels were lower or comparable to HIV mono-infected, tending to be higher thereafter. In MSM on cART, HCV had no significant effect on having a detectable VL.INTERPRETATION: Irrespective of the duration of HIV infection when HCV is acquired, CD4 counts were temporarily lower following HCVsc, even when on cART. The clinical implications of our findings remain to be further elucidated.
van Santen, D.K., van der Helm, J.J., Touloumi, G., Pantazis, N., Muga, R., Gunsenheimer-Bartmeyer, B., Gill, M.J., Sanders, E.,
Kelleher, A., Zangerle, R., Porter, K., Prins, M., Geskus, RB; CASCADE Collaboration within EuroCoord.