MedicalResearch: What is the background for this study? What are the main findings?
Dr. Morrison: The possible connection between hormonal contraception and HIV acquisition has been an open question for 25 years. Some studies have suggested that there is an increased risk associated with hormonal contraception, particularly with the 3-month injectable contraceptive called depot-medroxyprogesterone acetate (DMPA). Other studies have found that no such risk exists.
The World Health Organization (WHO) has held several technical consultations on this subject. WHO’s current guidelines state that “because of the inconclusive nature of the body of evidence on the possible increased risk of HIV acquisition, women using progestogen-only injectable contraception should be strongly advised to also always use condoms, male or female, and other HIV preventive measures.”
Two meta-analyses focusing on hormonal contraception and HIV acquisition have recently been published. One of them, FHI 360’s collaborative study, is an individual participant data meta-analysis. It found that users of injectable DMPA were 50 percent more likely to become infected with HIV than women not using hormonal contraceptives. For women using a different injectable progestin, norethisterone enanthate (NET-EN), or combined oral contraceptives (COC), the study investigators did not find a significantly increased risk of acquiring HIV compared to those who were not using hormonal contraceptives. Furthermore, DMPA users were 43 percent and 32 percent more likely to become infected with HIV compared to oral contraceptives users and NET-EN users, respectively.
It is important to point out a key secondary finding. The associations between hormonal contraception and risk of becoming infected with HIV were attenuated in studies that had a lower risk of methodological bias compared to those with higher risk of bias. This suggests that some of the risk found to be associated with hormonal contraception in fact may be attributed to inherent flaws in the nonrandomized studies themselves.
MedicalResearch: What should clinicians and patients take away from your report?
Dr. Morrison: This meta-analysis contributes to the growing body of evidence that demonstrates that depot-medroxyprogesterone acetate may be associated with an increased risk of HIV acquisition compared to women not using hormonal contraceptives and women using other types of hormonal contraceptives including oral contraceptives and NET-EN. However, because of the observational nature of the data in all the studies included in the meta-analysis, we need to be cautious about changing guidelines and counseling based on the study. Thus, women in regions with high HIV prevalence should be made aware that the use of DMPA may or may not increase their susceptibility to HIV acquisition, and should be advised to use condoms and take other HIV prevention measures.
MedicalResearch: What recommendations do you have for future research as a result of this study?
Dr. Morrison: The WHO has called for higher-quality evidence to inform policy makers, clinicians and women on this issue. The most robust evidence would be provided by a randomized trial of hormonal contraception and HIV acquisition. Such a randomized trial is now in the preparatory stages by a consortium that includes FHI 360, WHO, the Wits Reproductive Health and HIV Institute (WRHI) and the University of Washington.
Morrison CS1, Chen PL2, Kwok C2, Baeten JM3, Brown J4, Crook AM5, Van Damme L6, Delany-Moretlwe S7, Francis SC8, Friedland BA9, Hayes RJ8, Heffron R3, Kapiga S8, Karim QA10, Karpoff S11, Kaul R12, McClelland RS3, McCormack S4, McGrath N13, Myer L14, Rees H7, van der Straten A15, Watson-Jones D16, van de Wijgert JH17, Stalter R1, Low N18.