Risk factors for concordant HIV infection in heterosexual couples in Trinidad.

Risk factors for HIV infection in partners of HIV-seropositive index cases were investigated in a cross-sectional survey. Between September 1992 and April 1994 a total of 251 HIV-infected persons and 76 of their sexual partners were interviewed at the main sexually transmitted diseases (STDs) clinic in Trinidad. All participants gave signed consent and responded to a questionnaire. Sixty-four couples had risks for HIV infection through heterosexual intercourse only. However, many recruited sex partners (57/64) reported heterosexual intercourse with persons in addition to the index cases. Overall HIV concordance (both index case and partner HIV infected) was 45% in the couples. HIV concordance was not found to be related to the sexual practices within the studied unions nor to the clinical status of the index case. After allowing for confounding factors there was an increased risk for HIV concordance in couples in unions for > or = 1 year (adjusted OR 3.48; 95% CI 0.89-13.69, P = 0.055), and in those in which sex partners had a past history of genital sores (adjusted for prostitution: OR 4.50; 95% CI 1.01-20.4). Interventions targeted at reducing high-risk sexual behaviour, prostitution and cocaine use could be beneficial in reducing the spread of STDs and HIV in Trinidad.