title: Risk of HIV or second syphilis infection in Danish men with newly acquired syphilis in the period 2000-2010.
abstract: OBJECTIVE
  Risk of subsequent diagnosis of HIV in persons diagnosed with newly acquired syphilis, and syphilis in HIV-infected persons, are of interest as these infections are markers of unsafe sex.
  
  
  METHODS
  From a nationwide register, all Danish men aged >16 years diagnosed with syphilis in the period 2000-2010 (n=1217) were identified, and subsequently data on HIV status was extracted from the Danish HIV Cohort Study. We used Kaplan-Meier analysis to estimate the 5-year risk of HIV and second syphilis infection, and Cox regression to determine incidence rate ratios (IRR).
  
  
  RESULTS
  The 5-year risk of HIV diagnosis was 9.8% (95% CI 7.0% to 12.6%). Those with a second diagnosis of syphilis had a higher risk of being diagnosed with HIV (IRR=3.1, 95% CI 1.2 to 8.0). The 5-year risk for a second diagnosis of syphilis was 14.8% (95% CI 12.1% to 17.4%) and HIV-infected persons had a higher risk of a second syphilis diagnosis (IRR=4.0, 95% CI 2.8 to 5.9). Sixty-five percent of the persons were men having sex with men (MSM). Thirty-four percent of the HIV-infected persons had viral load >1000 copies/ml at time of syphilis diagnosis.
  
  
  CONCLUSIONS
  The substantial risks of syphilis and HIV infection in men diagnosed with one of these sexually transmitted diseases indicate a high frequency of unsafe sex in the Danish MSM population. As one-third of the HIV-infected persons diagnosed with syphilis had high viral loads, our data support initiation of antiretroviral therapy in all HIV-infected MSM to reduce HIV transmission.
authors.affiliation: Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark. ksalado@hotmail.com
authors.forename: Kirsten
authors.initials: K
authors.lastname: Salado-Rasmussen
authors.forename: Terese Lea
authors.initials: TL
authors.lastname: Katzenstein
authors.forename: Jan
authors.initials: J
authors.lastname: Gerstoft
authors.forename: Susan Alice
authors.initials: SA
authors.lastname: Cowan
authors.forename: Troels Bygum
authors.initials: TB
authors.lastname: Knudsen
authors.forename: Lars
authors.initials: L
authors.lastname: Mathiesen
authors.forename: Steen
authors.initials: S
authors.lastname: Hoffmann
authors.forename: Niels
authors.initials: N
authors.lastname: Obel
mesh_terms: D000293:Adolescent; D000328:Adult; D018791:CD4 Lymphocyte Count; D003718:Denmark / Q000453:epidemiology; D015658:HIV Infections / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012042:Registries; D012307:Risk Factors; D040242:Risk Reduction Behavior; D018571:Sentinel Surveillance; D012725:Sexual Behavior / Q000706:statistics & numerical data*; D013587:Syphilis / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control; D047568:Unsafe Sex / Q000517:prevention & control* / Q000706:statistics & numerical data; D019562:Viral Load