Seroprevalence and risk factors for HIV, hepatitis B and syphilis in populations with high-risk behaviors in Croatia

HIV and sexually-transmitted diseases (STDs) represent a significant public health problem worldwide. We analyzed the seroprevalence and risk factors for HIV, hepatitis B and syphilis in populations with high-risk behaviors in Croatia. During a three-year period, a total of 443 men who have sex with men (MSM) / bisexual persons, sex workers (SW) / clients of SW, persons with multiple sexual partners, and persons with a history of STD were tested for the presence of HIV, hepatitis B virus (HBV), and Treponema pallidum(syphilis) antibodies within the framework of second generation HIV surveillance. Participants were recruited from 11 Croatian counties, the vast majority among clients of voluntary counselling and testing centers. The overall prevalence of HIV, HBsAg, anti-HBc, and syphilis was 1.4%, 2.6%, 12.1%, and 3.4%, respectively. HBV and syphilis seroprevalence differed significantly between, genders with higher prevalence among men (anti- HBc 13.8% vs. 5.7%, P=0.043 ; syphilis 4.4% vs. 0% ; P=0.049), as well as between age groups, with a steady increase according to age. Participants with a history of STD were more often seropositive than participants who did not report STD (HBsAg 8.2% vs. 1.0%, P=0.002 ; anti-HBc 32.4% vs. 6.4%, P<0.001 ; syphilis 12.0% vs. 1.7%, P<0.001). Syphilis seroprevalence was higher in homo / bisexual persons(12.2%) compared with heterosexual persons (1.2%, P<0.001). Logistic regression showed that history of STD was a significant risk factor for hepatitis B (HBsAg AOR=6.229, 95% CI=1.491-26.022 ; anti-HBc AOR=5.872, 95% CI=2.899-11.896) and syphilis seropositivity (AOR=5.572, 95% CI=1.751-17.726), while homo / bisexual behavior was associated with syphilis seropositivity (AOR=12.820, 95% CI=3.688- 44.557). Our results highlight the importance of continuing STDs screening and prevention in at-risk populations.