title: Hepatitis C virus seroconversion among HIV-positive men who have sex with men with no history of injection drug use: Results from a clinical HIV cohort.
abstract: BACKGROUND
  Internationally, there is a growing recognition that hepatitis C virus (HCV) may be sexually transmitted among HIV-positive men who have sex with men (MSM).
  
  
  OBJECTIVE
  To report the first Canadian estimate of HCV seroincidence in 2000 to 2010 and its risk factors among HIV-positive MSM with no known history of injection drug use.
  
  
  METHODS
  Data from the Ontario HIV Treatment Network Cohort Study, an ongoing cohort of individuals in HIV care in Ontario, were analyzed. Data were obtained from medical charts, interviews and record linkage with the provincial public health laboratories. The analysis was restricted to 1534 MSM who did not report injection drug use and had undergone ≥2 HCV antibody tests, of which the first was negative (median 6.1 person-years [PY] of follow-up; sum 9987 PY).
  
  
  RESULTS
  In 2000 to 2010, 51 HCV seroconversions were observed, an overall incidence of 5.1 per 1000 PY (95% CI 3.9 to 6.7). Annual incidence varied from 1.6 to 8.9 per 1000 PY, with no statistical evidence of a temporal trend. Risk for seroconversion was elevated among men who had ever had syphilis (adjusted HR 2.5 [95% CI 1.1 to 5.5) and men who had acute syphilis infection in the previous 18 months (adjusted HR 2.8 [95% CI 1.0 to 7.9]). Risk was lower for men who had initiated antiretroviral treatment (adjusted HR 0.49 [95% CI 0.25 to 0.95]). There were no statistically significant effects of age, ethnicity, region, CD4 cell count or HIV viral load.
  
  
  CONCLUSIONS
  These findings suggest that periodic HCV rescreening may be appropriate in Ontario among HIV-positive MSM. Future research should seek evidence whether syphilis is simply a marker for high-risk sexual behaviour or networks, or whether it potentiates sexual HCV transmission among individuals with HIV.
authors: Ontario HIV Treatment Network; ; Dalla Lana School of Public Health, University of Toronto;
authors: Ann N
authors: AN
authors: Burchell
authors: Ontario HIV Treatment Network; ; Dalla Lana School of Public Health, University of Toronto;
authors: Sandra L
authors: SL
authors: Gardner
authors: Public Health Laboratories, Public Health Ontario; ; Department of Microbiology, Mount Sinai Hospital; ; Department of Laboratory Medicine and Pathobiology, University of Toronto;
authors: Tony
authors: T
authors: Mazzulli
authors: Ontario HIV Treatment Network;
authors: Michael
authors: M
authors: Manno
authors: Dalla Lana School of Public Health, University of Toronto; ; Toronto General Research Institute, University Health Network;
authors: Janet
authors: J
authors: Raboud
authors: Public Health Laboratories, Public Health Ontario;
authors: Vanessa G
authors: VG
authors: Allen
authors: Centre for Research on Inner City Health, The Keenan Research Centre in the Li KaShing Knowledge Institute, St Michael's Hospital; ; Institute of Health Policy, Management and Evaluation, University of Toronto; ; Department of Medicine, University of Toronto;
authors: Ahmed M
authors: AM
authors: Bayoumi
authors: Department of Medicine, University of Toronto;
authors: Rupert
authors: R
authors: Kaul
authors: AIDS Bureau, Ontario Ministry of Health and Long-Term Care;
authors: Frank
authors: F
authors: McGee
authors: Dalla Lana School of Public Health, University of Toronto;
authors: Peggy
authors: P
authors: Millson
authors: Dalla Lana School of Public Health, University of Toronto; ; Public Health Laboratories, Public Health Ontario;
authors: Robert S
authors: RS
authors: Remis
authors: Hotel Dieu Hospital; ; Queen's University, Kingston;
authors: Wendy
authors: W
authors: Wobeser
authors: Ottawa Hospital; ; University of Ottawa, Ottawa;
authors: Curtis
authors: C
authors: Cooper
authors: Ontario HIV Treatment Network; ; Centre for Research on Inner City Health, The Keenan Research Centre in the Li KaShing Knowledge Institute, St Michael's Hospital; ; Department of Psychiatry, University of Toronto.
authors: Sean B
authors: SB
authors: Rourke
keywords: HIV; Hepatitis C virus; Incidence; Men who have sex with men; Syphilis