Risk of HIV or second syphilis infection in Danish men with newly acquired syphilis in the period 2000–2010
- Kirsten Salado-Rasmussen1,
- Terese Lea Katzenstein1,
- Jan Gerstoft1,
- Susan Alice Cowan2,
- Troels Bygum Knudsen3,
- Lars Mathiesen3,
- Steen Hoffmann4,
- Niels Obel1
- 1Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- 2Department of Epidemiology, Statens Serum Institut, Copenhagen, Denmark
- 3Department of Infectious Diseases, Hvidovre University Hospital, Copenhagen, Denmark
- 4Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark
- Correspondence to Kirsten Salado-Rasmussen, Department of Infectious Diseases, M5132, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, Copenhagen Ø 2100, Denmark;
- Received 16 March 2012
- Revised 17 November 2012
- Accepted 26 November 2012
- Published Online First 27 December 2012
Objectives 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.