Background: Priority components of HIV prevention programs include intensified prevention efforts among those already known to be HIV infected and increasing the motivation of high-risk persons to know their infection status.  Crucial elements to address include monitoring high-risk behaviors (including acquisition of sexually transmitted diseases) in HIV-infected persons, and identifying high-risk persons who have never been tested. Our objectives were to assess HIV infection and HIV testing status in men with recently acquired, infectious syphilis and to identify factors associated with HIV testing and HIV infection among these high-risk men.

Methods: Data were abstracted from all reports of cases of infectious syphilis (primary, secondary, and early latent syphilis) in men reported to the Chicago Department of Public Health between January 1, 1998 and December 31, 2000. Demographic and behavioral risk factors were analyzed using univariate analysis and multivariate logistic regression. 

Results: Of the 1024 men with infectious syphilis, 194 (18.9%) were men who have sex with men (MSM) and 830 (81.1%) were heterosexual men. HIV infection status was known for 111/194 (57.2%) of the MSM and 325/830 (39.1%) of the heterosexual men. Of the 111 MSM, 54 (48.6%) were HIV-infected (HIV+), as were 23 (7.1%) of the 325 heterosexual men. Factors associated with HIV+ were: MSM, (odds ratio [OR] 12.39; 95% confidence interval [CI] 7.05-12.79), age < 35 (OR 1.75; 95% CI 1.05-2.95), and having > 5 sex partners within the past year (OR 2.98; 95% CI 1.55-5.73). Race was not associated with HIV+.  In multivariate regression analysis, only MSM was significantly associated with HIV+ (adjusted OR 9.8; 95% CI 5.1-18.7).  Of the 1024 men, 296 (28.9%) had never been HIV tested, including 50 (25.7%) of the MSM and 246 (29.6%) of the heterosexual men. MSM were more likely to have been HIV tested than heterosexual men (OR 1.6; 95% CI 1.15-2.3).  Race/ethnicity was not associated with HIV testing.  HIV testing history was unknown for 260 men, including 29 (14.9%) MSM and 231 (27.8%)  heterosexual men

Conclusion: MSM with infectious syphilis were 1.6 times more likely to have been tested for HIV infection and 10 times more likely to be HIV+ than heterosexual men. The high proportion of HIV infection among these men is concerning, suggesting a high level of unsafe sexual activity among persons with known HIV infection. As about a third of these men have not been tested for HIV infection, these data also demonstrate that a significant proportion of very high-risk men are not being tested for HIV and highlight the critical need to increase HIV testing and educational efforts among both MSM and high-risk heterosexual men.