Background Recent data suggest sexual transmission of hepatitis C virus (HCV). However, data on the association between HCV and sexually transmitted disease (STD) prevalence are limited.

Methods This was a retrospective cohort study of treatment-naïve HIV-infected adults ≥ 18 years first engaging at Washington University HIV Clinic from 2001 to 2009, who had routine STD and HCV antibody testing done. Gonorrhea, chlamydia, syphilis, and HCV cases were defined by positive urine nucleic acid amplification test for Neisseria gonorrhoeae, Chlamydia trachomatis, reactive serum rapid plasma reagin, and positive HCV antibody, respectively. Associations with HCV and STD using χ2, Student’s t, and Wilcoxon tests were determined.

Discussion Of 926 subjects (median age 32 years, 70% African American, 44% heterosexual, 42% men-who-have-sex-with-men [MSM], 4% injection drug users [IDU]), 8% had HCV (range 5–11%/year). Baseline STD was prevalent in 27% (18–34%/year). The prevalence of gonorrhoea, chlamydia and syphilis were 12% (7–21%/year), 12% (6–17%/year) and 10% (5–16%/year), respectively. Subjects with HCV were older (42 years, interquartile range [IQR 38–48] versus 31 years, [IQR 24–40]) (p < 0.001) and more likely to report past IDU (30% versus 2%) (p < 0.001) than those without. Male subjects with HCV were less likely to be MSM (28% vs 66%) (p < 0.001) and 36% of subjects with HCV were heterosexuals without past IDU. Subjects with HCV were less likely to have STD (17% vs 28%, p = 0.06), although this finding did not reach statistical significance. Furthermore, the number and type of STDs at presentation were not associated with prevalent HCV.

Conclusion Hepatitis C was prevalent in approximately 1 in 10 persons engaging in HIV outpatient care over nine years. A high prevalence of HCV among heterosexuals without past IDU suggests a possible role for sexual transmission of HCV not reflected by STD prevalence. Continued universal HCV screening among HIV-infected adults is imperative.