Human immunodeficiency virus infection in Mexico City. Rectal bleeding and anal warts as risk factors among men reporting sex with men.

ABSTRACT

PIP: During June 1991 to December 1992, 68.8% of all men who gave informed consent for HIV testing at a public health clinic in Mexico City and for participation in this study had ever had sexual intercourse with men. The final sample size was 2758 men. The study examined the reported frequency of rectal bleeding, the determinants of rectal bleeding, and the interactions between rectal bleeding and other risk factors with HIV infection among homosexual/bisexual men. It also aimed to determine whether rectal bleeding is an independent risk factor for HIV transmission. 32.8% had HIV infection. 39% reported some rectal bleeding during anal intercourse. 8% experienced rectal bleeding during at least 50% of intercourse episodes. Overall, bleeders were more likely to be HIV infected than nonbleeders (42% vs. 28%; p 0.0001; adjusted odds ratio [AOR] = 1.8 for men who bled in more than 50% of anal intercourse episodes; AOR = 1.3 for men who sometimes bled). The odds ratios increased as the frequency of reported rectal bleeding increased (p = 0.001). Condom use during receptive anal intercourse did not affect the association between rectal bleeding and HIV infection. 9% of all HIV infections were attributable to rectal bleeding. 42% of HIV infections among bleeders were attributable to rectal bleeding. In the multivariate analysis, men with both rectal bleeding and anal warts were more likely to have HIV infection than men who had neither (67.9% vs. 27.2%; AOR = 3.5). Significant predictors of rectal bleeding were older age (i.e., =or 30) (AOR = 1.5), more education (AOR = 1.4-1.5), more receptive anal intercourse than insertive intercourse (AOR = 5.3-16.1), receptive digital-anal contact (AOR = 1.6), anal warts (AOR = 1.9), and genital ulcers (AOR = 2). These findings show that rectal bleeding is an independent risk factor for HIV infection. Rupture of anal warts is an especially effective portal of HIV transmission.