title: Condom effectiveness for reducing transmission of gonorrhea and chlamydia: the importance of assessing partner infection status.
abstract: This analysis examined the importance of differential exposure to infected partners in epidemiologic studies of latex condom effectiveness for prevention of sexually transmitted infections. Cross-sectional, enrollment visit data were analyzed from Project RESPECT, a trial of counseling interventions conducted at five publicly funded US sexually transmitted disease clinics between 1993 and 1997. The association between consistent condom use in the previous 3 months and prevalent gonorrhea and chlamydia (Gc/Ct) was compared between participants known to have infected partners and participants whose partner infection status was unknown. Among 429 participants with known Gc/Ct exposure, consistent condom use was associated with a significant reduction in prevalent gonorrhea and chlamydia (30% vs. 43%; adjusted prevalence odds ratio = 0.42, 95% confidence interval: 0.18, 0.99). Among 4,314 participants with unknown Gc/Ct exposure, consistent condom use was associated with a lower reduction in prevalent gonorrhea and chlamydia (24% vs. 25%; adjusted prevalence odds ratio = 0.82, 95% confidence interval: 0.66, 1.01). The number of unprotected sex acts was significantly associated with infection when exposure was known (p for trend < 0.01) but not when exposure was unknown (p for trend = 0.73). Restricting analyses to participants with known exposure to infected partners provides a feasible and efficient mechanism for reducing confounding from differential exposure to infected partners in condom effectiveness studies.
authors.affiliation: National Center for HIV, STD and TB Prevention, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. dlw7@cdc.gov
authors.forename: Lee
authors.initials: L
authors.lastname: Warner
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Newman
authors.forename: Harland D
authors.initials: HD
authors.lastname: Austin
authors.forename: Mary L
authors.initials: ML
authors.lastname: Kamb
authors.forename: John M
authors.initials: JM
authors.lastname: Douglas
authors.forename: C Kevin
authors.initials: CK
authors.lastname: Malotte
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Zenilman
authors.forename: Judy
authors.initials: J
authors.lastname: Rogers
authors.forename: Gail
authors.initials: G
authors.lastname: Bolan
authors.forename: Martin
authors.initials: M
authors.lastname: Fishbein
authors.forename: David G
authors.initials: DG
authors.lastname: Kleinbaum
authors.forename: Maurizio
authors.initials: M
authors.lastname: Macaluso
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Peterman
mesh_terms: D000328:Adult; D002690:Chlamydia Infections / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission; D017280:Condoms / Q000706:statistics & numerical data*; D004522:Educational Status; D005260:Female; D006069:Gonorrhea / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission; D006801:Humans; D016015:Logistic Models; D008297:Male; D012725:Sexual Behavior / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology