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Effect of Contraceptive Methods on Natural History of HIV: Studies from the Mombasa Cohort

Farley, Tima; Mwachari, Christinab; Cohen, Craigb,c; Chipato, Tsungaid; Jaisamrarn, Unope; Kiriwat, Orawanf; Duerr, Anng

JAIDS Journal of Acquired Immune Deficiency Syndromes: March 2005 - Volume 38 - Issue - p S20–S21
doi: 10.1097/

aDepartment of Reproductive Health and Research, World Health Organization, Geneva, Switzerland

bKenya Medical Research Institute, Nairobi, Kenya

cUniversity of Washington, Seattle, WA, USA

dDepartment of Obstetrics and Gynaecology, University of Zimbabwe, Zimbabwe

eDepartment of Obstetrics and Gynaecology, Chulalongkorn University, Bangkok, Thailand

fDepartment of Obstetrics and Gynaecology, Siriraj Hospital, Mahidol University, Bangkok, Thailand

gDivision of Reproductive Health, Centers for Disease Control, Atlanta, GA, USA

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To assess the effect of steroid hormone contraceptive methods on the clinical course of early HIV infection among women in Kenya, Thailand and Zimbabwe.

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Women with documented HIV infection and CD4 cell counts over 500 cells/μl who were asymptomatic or had early (mild disease) were invited to participate in an observational cohort study with 6-monthly follow-up visits for 4 years. Baseline information was collected through interview, physical examination and blood sample collection for CD4 cell count, HIV quantification and subtyping. Identical procedures were repeated at each follow-up visit. Study endpoints include HIV disease progression, the incidence of opportunistic infections (OI), and surrogate markers of disease progression, including changes in CD4 cell counts and viral load. These will be analysed according to the contraceptive methods used. The study aimed to recruit a total of 220 users each of DMPA, Norplant, COC and a similar number of women not using hormonal contraception over the study sites.

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Recruitment to the study started in 2000 and by the middle of 2002 a total of 395 women had been recruited, the majority of whom were from Nairobi (52%) and Harare (23%). One quarter of women were using COC, 42% DMPA, 5% Norplant and the remaining 28% non-hormonal contraception at enrolment. Almost all the Norplant users were from Bangkok and almost all the COC and DMPA users were from the two African sites. Few HIV endpoints have occurred in the cohort to date. CD4 cell counts at enrolment were lower in Harare than in Nairobi, despite the selection of women with counts above 500 cells/μl. Preliminary assessment of the rates of CD4 cell decline showed a higher rate in Harare (mean annual loss of 102 cells/μl; SD 244) than in Nairobi (mean annual loss of 55 cells/μl; SD 283). Recruitment into the cohort continued through 2003 and follow-up will continue for the enrolled women up to the scheduled four completed years. The study is estimated to have 80% power to demonstrate twofold differences in the rates of CD4 cell decline between oral contraceptive and non-hormonal users, as well as between DMPA and non-hormonal users.

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Recruitment into the study has been difficult, particularly as the study was not able to offer any promise of therapy for HIV-positive women. Plans to provide antiretroviral therapy to those women whose CD4 cell counts decline below 200 cells/μl are under development and will allow the clinical response to antiretroviral therapy to be assessed in the well-documented cohort of steroid hormone contraception users. Recruitment to the study had to be abandoned in Brazil as the national standards for therapy meant that there would at best be only a short period of observation before the volunteers qualified for treatment, and it proved very difficult to identify HIV-positive women with CD4 cell counts over the study threshold for enrolment.

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Financial support for the study was provided by the World Health Organization Special Programme of Research, Development and Research Training in Human Reproduction (HRP), Geneva, Switzerland.

© 2005 Lippincott Williams & Wilkins, Inc.