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Wednesday, May 10, 2006

Male circumcision and risk of HIV infection among heterosexual men attending Baltimore STD clinics: an evaluation of clinic-based data

Lee Warner1, Khalil G. Ghanem2, Daniel R. Newman3, Maurizio Macaluso1, and Emily Erbelding4. (1) NCCDPHP/DRH, Centers for Disease Control and Prevention, 4770 Buford Highway NE, Mailstop K-34, Atlanta, GA, USA, (2) Division of Infectious Disease, Johns Hopkins University School of Medicine, Johns Hopkins-Bayview Medical Center, 4940 Eastern Ave., B-3 North, Baltimore, MD, USA, (3) NCHHSTP/DSTDP/ESB, Centers for Disease Control and Prevention, 1600 Clifton Road, MS:E-02, Atlanta, GA, USA, (4) Baltimore City Health Department and, Johns Hopkins University School of Medicine, Baltimore, MD, USA

Male circumcision has received international attention as an intervention for reducing HIV acquisition among high-risk heterosexual men. Few U.S. studies have evaluated circumcision for HIV prevention among heterosexual men.

To examine the association between circumcision and HIV infection among two STD clinic populations.

Data were analyzed from clinic records of heterosexual, non-injecting, African-American male patients who received HIV testing while attending Baltimore STD clinics from 1993-2000. Multivariable logistic regression was used to evaluate the association between circumcision and HIV prevalence among all clinic visits (n=40,571) and clinic visits where patients had known HIV exposure (i.e., patients were recently contacted by DIS of their exposure to HIV-infected partners) (n=394, 1% of visits). Analyses were adjusted for age, prior STD history, penile ulcer, symptoms, and visit year.

Most visits were among men who were circumcised (87%), >25 years old (63%), and had self-reported STD history (78%). HIV prevalence was lower among all visits compared with visits with known exposure (2.7% vs. 11.7%). Among all visits, circumcision was not associated with reduced HIV prevalence [2.5% vs 3.3%, aOR = 0.88 (0.75-1.05)] while sexual contact with HIV-infected partners [aOR=3.3 (2.4-4.6)], penile ulcer [aOR=2.8 (2.1-3.7)], age>25 [aOR=3.3 (2.9-4.1)], and prior STD history [aOR=1.5 (1.2-1.8)] were associated with increased prevalence. Among visits with known exposure, circumcision was significantly associated with reduced HIV prevalence [10.2% vs 22.0%, aOR=0.42 (0.20-0.92)]. No other factors were associated with HIV prevalence.

Associations between circumcision and HIV observed from STD clinic record data varied depending on the population studied. Analyses restricted to patients with known exposure yield higher HIV prevalence, ensure exposure occurred across compared groups, and suggest circumcision may reduce HIV risk in heterosexual men, as reported in recent randomized trials.

The protective effect of circumcision against HIV acquisition may have been underestimated in prior observational studies because of bias.