[Risk factors for the heterosexual transmission of HIV from man to woman: a Spanish multicenter study]. / Factores de riesgo para la transmisión heterosexual del VIH de varón a mujer: un estudio multicéntrico español.

ABSTRACT

PIP: The objectives of this study, which formed part of the Multicenter European Study of Heterosexual Transmission, were to estimate the rate of heterosexual HIV transmission in a population of intravenous drug users, to describe the sexual and contraceptive habits of the couples, and to identify possible risk factors for heterosexual HIV transmission. 130 couples from 17 centers in Andalusia, Cataluna, and Madrid, who met the criteria and agreed to participate, were studied between June 1988 and February 1990. The index case in all couples was a male partner seropositive for HIV infection. Exclusion criteria for the female partner included intravenous drug use, blood transfusion since 1980, or sexual relations in the past 6 months with an individual other than the index case. All women were screened for HIV antibodies with the ELISA test, with confirmation of positive results by Western blot or indirect immunofluorescence. Around 70% of participants in center collecting sociodemographic information were illiterate of had primary educations, and over half had children. 40% of the index cases had a history of sexual contacts with prostitutes, over 20% reported more than 5 sexual partners in the past 5 years, and 18% had had other sexual partners in addition to the partner interviewed since learning of their seropositivity. Over half of couples had been together for more than 5 years. 32% of the women reported other sexual partners in the past 5 years, excluding the past 6 months. 70% of the couples interviewed reported having sexual relations 1-3 times weekly. 25% reported having anal intercourse. 33% of the men and 17% of the women reported a history of sexually transmitted diseases. 11 additional cases of sexually transmitted disease in men and 8 in women were diagnosed in the study. The rate of transmission was 16% (21/130), with a 95% confidence interval between 10-22.4%. The risk factors significantly associated with HIV transmission were: index case over 30 years old (odds ratio of 3.1), clinical stage 4 (odds ratio 4.1), lymphocyte level under 800 (odds ratio of 7), history of sexually transmitted diseases in the woman (odds ratio of 4), and practice of anal intercourse (odds ratio of 3.1). The clinical stage of the index case and history of sexually transmitted disease in the woman were the only risk factors statistically significant in multivariate analysis. The lymphocyte population was omitted from the multivariate analysis, since it was known for only 63 men. The possible effect of condom use could not be determined because only 4 couples used them regularly.