Hormonal contraception does not increase women's HIV acquisition risk in Zambian discordant couples, 1994–2012
Published Date:Feb 21 2015
Source:Contraception. 2015; 91(6):480-487.
Contraceptives, Oral, Hormonal
Proportional Hazards Models
Pubmed Central ID:PMC4442041
Funding:P30 AI050409/AI/NIAID NIH HHS/United States
R01 AI040951/AI/NIAID NIH HHS/United States
R01 HD040125/HD/NICHD NIH HHS/United States
R01 AI051231/AI/NIAID NIH HHS/United States
5U2GPS000758/PHS HHS/United States
D43TW001042/TW/FIC NIH HHS/United States
R01 AI64060/AI/NIAID NIH HHS/United States
R01 HD40125/HD/NICHD NIH HHS/United States
R01 AI023980/AI/NIAID NIH HHS/United States
R37 AI051231/AI/NIAID NIH HHS/United States
R01 AI064060/AI/NIAID NIH HHS/United States
D43 TW001042/TW/FIC NIH HHS/United States
R01 MH066767/MH/NIMH NIH HHS/United States
R37 AI51231/AI/NIAID NIH HHS/United States
U2G PS000758/PS/NCHHSTP CDC HHS/United States
R01 AI51231/AI/NIAID NIH HHS/United States
R01 66,767/PHS HHS/United States
To determine the impact of hormonal contraceptive methods on risk of HIV acquisition among HIV-negative women cohabiting with HIV-positive male partners.
From 1994–2012, HIV discordant couples recruited from a couples’ voluntary HIV counseling and testing center in Lusaka, Zambia were followed longitudinally. HIV-negative partners were tested quarterly. This analysis is restricted to couples in which the man was HIV-positive and the woman was HIV-negative at enrollment and the man was not on antiretroviral treatment. Multivariate Cox models evaluated associations between time-varying contraceptive methods and HIV acquisition among women. Sensitivity analyses explored exposure misclassification and time-varying confounder mediation.
Among 1393 couples, 252 incident infections occurred in women over 2842 couple-years (8.9 infections per 100 couple-years; 95% CI, 7.8–10.0). Multivariate Cox models indicated that neither injectable [adjusted hazard ratio (aHR)=1.2; 95% CI, 0.8–1.7], oral contraceptive pill (OCP, aHR=1.3; 95% CI, 0.9–1.8), or implant (aHR=1.1; 95% CI, 0.5–2.2) use was significantly associated with HIV acquisition relative to non-hormonal contraception controlling for woman's age, literacy and time-varying measures of genital ulceration/inflammation. This remained true when only looking at the subset of infections acquired from the spouse (82% of infections) and additionally controlling for baseline HIV viral load of the male partner, pregnancy status, and time-varying measures of sperm on a vaginal swab wet prep and self-reported unprotected sex. OCP and injectable users reported more unprotected sex (p<.001), and OCP users were more likely to have sperm on vaginal swab (p=.1) than nonhormonal method users.
We found no association between hormonal contraception and HIV acquisition risk in women. Condom use and reinforced condom counseling should always be recommended for HIV discordant couples. HIV testing of sex partners together is critical to establish HIV risk, ascertain couple fertility intentions and counsel appropriately.
These findings add to a controversial literature and uniquely address several common design and analytic challenges faced by previous studies. After controlling for confounders, we found no association between hormonal contraception and HIV acquisition risk in women. We support promoting condoms for HIV prevention and increasing the contraceptive method mix to decrease unintended pregnancy.
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