Absolute and attributable risk of venous thromboembolism in women on combined cyproterone acetate and ethinylestradiol.
OBJECTIVE
To achieve absolute risk estimates of venous thromboembolism (VTE) among women on cyproterone acetate plus ethinylestradiol (CPA/EE), and among women on combined oral contraceptives (COCs).


METHODS
From the Danish National Register of Patients (NRP), 1996 to 1998, the records of 1.1 million Danish women, ages 15 to 44 years, were searched for evidence of VTE. COC use was ascertained through mailed questionnaires. Sales statistics of COCs and CPA/EE were provided through Danish Drug Statistics.


RESULTS
During the time frame of the study, 330 women were found to have had VTE while on COCs. Of these women, 67 were on levonorgestrel-containing COCs. Eleven were on CPA/EE. The corresponding absolute risk of VTE was 3.4 (range, 3.1-3.8) per 10 000 women years among the women on COCs, 4.2 (range, 3.2-5.2) per 10 000 women years among women on levonorgestrel-containing COCs, and 3.1 (range, 1.3-4.9) per 10 000 women years among the women on CPA/EE.


CONCLUSIONS
Our results suggest the absolute risk of VTE among Danish women on COCs is similar to that among women taking CPA/EE.
Lidegaard
Øjvind
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Danish Centre for Human Reproductive Epidemiology (DaHRE), Department of Obstetrics and Gynaecology, Herlev University Hospital, Copenhagen County, Denmark.
D000293:Adolescent; D000328:Adult; D003277:Contraceptives, Oral, Combined / Q000008:administration & dosage / Q000009:adverse effects*; D017373:Cyproterone Acetate / Q000008:administration & dosage / Q000009:adverse effects*; D003718:Denmark / Q000453:epidemiology; D016021:Epidemiologic Studies; D004997:Ethinyl Estradiol / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D006801:Humans; D018570:Risk Assessment; D012307:Risk Factors; D013923:Thromboembolism / Q000139:chemically induced* / Q000453:epidemiology*; D020246:Venous Thrombosis / Q000139:chemically induced / Q000453:epidemiology
D003277:Contraceptives, Oral, Combined; D004997:Ethinyl Estradiol; D017373:Cyproterone Acetate