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Published on: July 6, 2014
Using changes in binding globulins to assess oral contraceptive compliance
Carolyn L Westhoff1, Kelsey A Petrie, Serge Cremers
1Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY 10032, USA. clw3@columbia.edu
Contraception
|July 17, 2012
Summary
Measuring changes in corticosteroid-binding globulin (CBG) and thyroxine-binding globulin (TBG) effectively identifies noncompliant oral contraceptive pill (OCP) users in clinical trials. These binding globulin increases serve as reliable markers for OCP compliance.
Area of Science:
- Pharmacology
- Endocrinology
- Clinical Trials
Background:
- Oral contraceptive pill (OCP) clinical trial validity hinges on participant compliance.
- Ethinyl estradiol (EE2) in OCPs elevates hepatic binding globulin (BG) levels.
- Monitoring BG changes offers a method to assess OCP user compliance in research.
Purpose of the Study:
- To evaluate the utility of corticosteroid-, sex-hormone-, and thyroxine-binding globulin (CBG, SHBG, TBG) increases as indicators of OCP compliance.
- To determine if BG changes can differentiate compliant from noncompliant OCP users.
Main Methods:
- Serum samples from a trial comparing normal-weight and obese women using OCPs with EE2 and levonorgestrel (LNG) were analyzed.
- Participants were categorized as compliant or noncompliant (17%) based on serial LNG measurements.
- Changes in CBG, SHBG, and TBG from baseline to 3-month follow-up were compared between groups using receiver operator characteristic (ROC) curves.
Main Results:
- Increases in CBG and TBG significantly distinguished noncompliant from compliant OCP users (AUROC 0.86 and 0.89, p<.01).
- Sex-hormone-binding globulin (SHBG) changes showed less discrimination (AUROC 0.69).
Conclusions:
- Elevated CBG and TBG levels induced by EE2 are sensitive and integrated markers of compliance.
- These binding globulins provide a reliable method for assessing adherence to levonorgestrel-containing OCPs in research settings.
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