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Tamoxifen and risk of idiopathic venous thromboembolism

Christoph Rudolf Meier, Hershel Jick

British Journal of Clinical Pharmacology, 1998

10,000 participants · 184 citations

Abstract

AIMS: To evaluate a possible positive association between tamoxifen treatment and the risk of developing idiopathic venous thromboembolism (VTE) in women with breast cancer in the absence of clinical risk factors for venous thromboembolism other than breast cancer itself. METHODS: Using information from the large UK-based General Practice Research Database, we identified, within a cohort of more than 10000 women with breast cancer, all women who developed a first-time diagnosis of deep vein thrombosis or pulmonary embolism of uncertain cause between January 1, 1991 and December 31, 1996. In a case-control analysis, we compared their tamoxifen exposure experience prior to the thromboembolic event with that of a randomly selected group of control women with breast cancer who were matched to cases on age, year of the breast cancer diagnosis and calendar time. RESULTS: We identified 25 cases of idiopathic VTE and 172 controls, all of whom had breast cancer, but were otherwise free from other risk factors for VTE. Past tamoxifen exposure was not materially associated with an elevated risk of developing VTE, and we therefore combined never and past users as reference group. The relative risk estimate of VTE for current tamoxifen exposure, as compared with never and past use combined, was 7.1 (95% CI 1.5-33), adjusted for body mass index, smoking status and hysterectomy status. High body mass index was an independent predictor of VTE itself. CONCLUSIONS: Our study provides evidence…

How strong is the evidence?

Evidence Hub reads this as a case-control, done in people. Its evidence level is 4 of 5 (Low · observational). Observational designs can show an association but not prove cause. Reported size: 10,000 participants or records.

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