Effects of switching from oral to transdermal or transvaginal contraception on markers of thrombosis☆☆☆
Received 8 May 2008; received in revised form 2 July 2008; accepted 3 July 2008. published online 01 September 2008.
Abstract
Background
The study was conducted to determine the impact of switching from oral to transdermal patch or vaginal ring contraception on biomarkers of thrombosis.
Study Design
Current healthy oral contraceptive (OC) users were randomized to switch to either a contraceptive ring (CR) or patch (CP) and underwent phlebotomy to measure surrogate biomarkers of thrombosis [sex hormone-binding globulin (SHBG), free protein S and activated protein C resistance (APC-r)] before switching, and during the fourth cycle of use of the new method.
Results
Of 142 reproductive age women enrolled, 120 sample pairs were available for analysis. SHBG increased significantly from baseline in CP users [mean change (95% CI), +29.9 nM (9.6–50)] but not in CR users [−1.6 (−16.6 to 13.5)]. Protein S decreased significantly from baseline in CP users [mean change −7.1% (−12.1 to −2.1)], but increased significantly in CR users [+5.3% (1.1–9.6)]. The APC-r ratio did not undergo a significant change from baseline in either group [CP +0.06 (−0.06 to 0.18), CR +0.02 (−0.10 to 0.14)]. Compared to CR users, subjects using the CP had significantly higher SHBG [187.5 (167.0–208), 146 (132.6–159.4), p=.012], significantly lower protein S [81.8 (76.8–86.8), 93.6 (89.1–98.1), p=.001] and similar APC-r ratios [2.99 (2.85–3.14), 3.09 (2.96, 3.22), p=.3] at the Cycle 4 visit.
Conclusion
OC users who switch to the ring exhibit beneficial changes in biomarkers of thrombosis, while those switching to the patch display a shift favoring clot formation.
aDepartment of Obstetrics and Gynecology, Oregon Health and Science University, Portland, OR 97239, USA
bDepartment of Obstetrics and Gynecology, Johns Hopkins University, Baltimore, MD 21205, USA
cDepartment of Obstetrics and Gynecology, and Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, PA 19104, USA
dDepartment of Public Health and Preventive Medicine, Oregon Health and Science University, Portland, OR 97239, USA
eBiostatistics Shared Resource, Oregon Health and Science University, Portland, OR 97239, USA
Corresponding author. Mail code UHN-70 Oregon Health and Science University, Portland, OR 97239, USA. Tel.: +1 503 494 4469; fax: +1 503 494 5083.
☆ This publication was made possible in part with biostatistics support from the Biostatistics Shared Resource of Oregon Health and Science University and laboratory support from the Oregon Clinical and Translational Research Institute (OCTRI), grant numbers UL1 RR024140 01 and M01 RR000334 from the National Center for Research Resources (NCRR), a component of the National Institutes of Health (NIH) and NIH Roadmap for Medical Research. Funding for the main study was directly from the Magee-Women's Research Institute Foundation using funds from Organon USA. Organon USA, Inc., played no role in the design of either study; in the acquisition, analysis and interpretation of the data; in the drafting or revision of the manuscript; or technical support or supervision of the study.
☆☆ Conflict of interest: Dr. Jensen: research funding: Bayer, Organon, Galen, Symbollon, Wyeth, Pfizer, Novartes; speakers bureau: Bayer, Wyeth; consulting: Bayer, Wyeth, Novartes. Dr. Burke: research funding: Organon, Duramed, Bayer. Dr. Barnhart: research funding: Organon, Wyeth-Ayerst, Johnson & Johnson, Duramed, Xanodyne, Boehringer Ingelheim, Third Wave, Pfeizer, MGI Pharma; speakers bureau: Organon; consulting: Novo Nordisk. Dr. Peters, Ms. Messerle-Forbes and Ms. Tillotson: no conflicts.
ABSTRACT