title: Patterns of syphilis testing in a large cohort of HIV patients in Ontario, Canada, 2000-2009.
abstract: BACKGROUND
  Since 2000, reported syphilis cases increased ten-fold in Canada, particularly among men who have sex with men (MSM) co-infected with HIV. We characterized temporal patterns of of syphilis testing in a large cohort of HIV patients in Ontario, Canada.
  
  
  METHODS
  We analyzed data from a multi-site cohort of people in HIV care from 2000 to 2009. Data were obtained from medical charts, interviews and record linkage with the syphilis test database at the Public Health Ontario Laboratories. We estimated the proportion that had syphilis testing at least once per year and the period and annual prevalence of reactive tests.
  
  
  RESULTS
  Among 4232 participants, the annual proportion tested rose from 2.7% (95%CI 1.9, 3.5) in 2000 to 54.6% (95%CI 52.9, 56.3) in 2009. Testing was most common for participants who were men who have sex with men (MSM), aged <30, recently diagnosed with HIV, were antiretroviral treatment naive, had routine HIV lab testing at least twice in that year, or tested for syphilis in the preceding year. The proportion with at least one reactive test in 2000-09 was 21.0% (95%CI 19.4, 22.7) for MSM, 5.3% (95%CI 3.3, 7.4) for non-MSM males, and 2.6% (95%CI 1.2, 4.0) for women. Among MSM, the annual prevalence of reactive syphilis tests with high RPR titre (≥1:16) peaked at 3.8% in 2009.
  
  
  CONCLUSIONS
  The burden of syphilis co-infection rose considerably among HIV-positive MSM, such that by 2009, at least 1 in 5 men had laboratory evidence of current or past infection. Interventions may be needed to boost syphilis testing to achieve goals set by guidelines even in settings with universal health care.
authors.affiliation: Ontario HIV Treatment Network, Suite 600, 1300 Yonge Street, Toronto, Ontario M4T 1X3, Canada. aburchell@ohtn.on.ca
authors.forename: Ann N
authors.initials: AN
authors.lastname: Burchell
authors.forename: Vanessa G
authors.initials: VG
authors.lastname: Allen
authors.forename: Veronika
authors.initials: V
authors.lastname: Moravan
authors.forename: Sandra
authors.initials: S
authors.lastname: Gardner
authors.forename: Janet
authors.initials: J
authors.lastname: Raboud
authors.forename: Darrell H S
authors.initials: DH
authors.lastname: Tan
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Bayoumi
authors.forename: Rupert
authors.initials: R
authors.lastname: Kaul
authors.forename: Tony
authors.initials: T
authors.lastname: Mazzulli
authors.forename: Frank
authors.initials: F
authors.lastname: McGee
authors.forename: Peggy
authors.initials: P
authors.lastname: Millson
authors.forename: Robert S
authors.initials: RS
authors.lastname: Remis
authors.forename: Sean B
authors.initials: SB
authors.lastname: Rourke
mesh_terms: D000328:Adult; D015331:Cohort Studies; D060085:Coinfection / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D015658:HIV Infections / Q000453:epidemiology / Q000382:microbiology*; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000706:statistics & numerical data; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D015995:Prevalence; D013587:Syphilis / Q000175:diagnosis / Q000453:epidemiology / Q000821:virology*