An updated systematic review of epidemiological evidence on hormonal contraceptive methods and HIV acquisition in women

Chelsea B. Polis, Kathryn M. Curtis, Philip C. Hannaford, Sharon J. Phillips, Tsungai Chipato, James N. Kiarie, Daniel J. Westreich, Petrus S. Steyn

Some studies suggest that specific hormonal contraceptive (HC) methods (particularly depot medroxyprogesterone acetate [DMPA]) may increase women's HIV acquisition risk. We updated a systematic review to incorporate recent epidemiological data. We searched for articles published between 1/15/2014-1/15/2016, and hand-searched reference lists. We identified longitudinal studies comparing users of a specific HC method against either (1) non-users of HC, or (2) users of another specific HC method. We added newly identified studies to those in the previous review, assessed study quality, created forest plots to display results, and conducted a meta-analysis for data on DMPA versus no HC. We identified ten new reports: five were considered "unlikely to inform the primary question". We focus on the other five reports, along with 9 from the previous review, considered "informative but with important limitations". The preponderance of data for oral contraceptive pills, injectable norethisterone enanthate (NET-EN), and levonorgestrel implants do not suggest an association with HIV acquisition, though data for implants are limited. The new, higher-quality studies on DMPA (or non-disaggregated injectables), which had mixed results in terms of statistical significance, had hazard ratios (HR) between 1.2 and 1.7, consistent with our meta-analytic estimate for all higher-quality studies of HR 1.4. While confounding in these observational data cannot be excluded, new information increases concerns about DMPA and HIV acquisition risk in women. If the association is causal, the magnitude of effect is likely ≤HR 1.5. Data for other hormonal contraceptive methods, including NET-EN, are largely reassuring.