Risk assessment for recurrent venous thrombosis

Abstract

In the Review entitled “Risk assessment for recurrent venous thrombosis” (Dec 11, p 2032),1Kyrle PA Rosendaal FR Eichinger S Risk assessment for recurrent venous thrombosis.Lancet. 2010; 376: 2032-2039Summary Full Text Full Text PDF PubMed Scopus (209) Google Scholar Paul Kyrle and colleagues report that women who continued hormone intake after a first event of venous thromboembolism (VTE) were at high risk of recurrent VTE. However, findings from a French cohort of postmenopausal women emphasise that the risk of recurrent VTE in users of hormone therapy depended on the route of oestrogen administration.Consistent with previous data,2Hoibraaten E Qvigstad E Arnesen H Larsen S Wickstrom E Sandset PM Increased risk of recurrent venous thromboembolism during hormone replacement therapy—results of the randomized, double-blind, placebo-controlled estrogen in venous thromboembolism trial (EVTET).Thromb Haemost. 2000; 84: 961-967PubMed Google Scholar women using oral oestrogens after a first thrombotic event were at high risk of recurrent VTE (adjusted hazard ratio 6·4, 95% CI 1·5–27·3). By contrast, transdermal oestrogens were not associated with an increased risk of recurrent VTE compared with non-use (1·0, 0·4–2·4).3Olie V, Plu-Bureau G, Conard J, Horellou MH, Canonico M, Scarabin PY. Hormone therapy and recurrence of venous thromboembolism among postmenopausal women. Menopause (in press).Google Scholar These data provide evidence to support the safety of the transdermal route of oestrogen administration with respect to the risk of VTE recurrence and add to the current epidemiological evidence that transdermal oestrogens have no effect on thrombotic risk in postmenopausal women.4Olie V Canonico M Scarabin PY Risk of venous thrombosis with oral versus transdermal estrogen therapy among postmenopausal women.Curr Opin Hematol. 2010; 17: 457-463Crossref PubMed Scopus (105) Google Scholar, 5Scarabin PY Oger E Plu-Bureau G Differential association of oral and transdermal oestrogen-replacement therapy with venous thromboembolism risk.Lancet. 2003; 362: 428-432Summary Full Text Full Text PDF PubMed Scopus (666) Google ScholarIn light of these data, the evidence for the implication of continuous oestrogen use in the increased risk of recurrent venous thrombosis should be modulated according to the route of oestrogen administration in postmenopausal women.We declare that we have no conflicts of interest. In the Review entitled “Risk assessment for recurrent venous thrombosis” (Dec 11, p 2032),1Kyrle PA Rosendaal FR Eichinger S Risk assessment for recurrent venous thrombosis.Lancet. 2010; 376: 2032-2039Summary Full Text Full Text PDF PubMed Scopus (209) Google Scholar Paul Kyrle and colleagues report that women who continued hormone intake after a first event of venous thromboembolism (VTE) were at high risk of recurrent VTE. However, findings from a French cohort of postmenopausal women emphasise that the risk of recurrent VTE in users of hormone therapy depended on the route of oestrogen administration. Consistent with previous data,2Hoibraaten E Qvigstad E Arnesen H Larsen S Wickstrom E Sandset PM Increased risk of recurrent venous thromboembolism during hormone replacement therapy—results of the randomized, double-blind, placebo-controlled estrogen in venous thromboembolism trial (EVTET).Thromb Haemost. 2000; 84: 961-967PubMed Google Scholar women using oral oestrogens after a first thrombotic event were at high risk of recurrent VTE (adjusted hazard ratio 6·4, 95% CI 1·5–27·3). By contrast, transdermal oestrogens were not associated with an increased risk of recurrent VTE compared with non-use (1·0, 0·4–2·4).3Olie V, Plu-Bureau G, Conard J, Horellou MH, Canonico M, Scarabin PY. Hormone therapy and recurrence of venous thromboembolism among postmenopausal women. Menopause (in press).Google Scholar These data provide evidence to support the safety of the transdermal route of oestrogen administration with respect to the risk of VTE recurrence and add to the current epidemiological evidence that transdermal oestrogens have no effect on thrombotic risk in postmenopausal women.4Olie V Canonico M Scarabin PY Risk of venous thrombosis with oral versus transdermal estrogen therapy among postmenopausal women.Curr Opin Hematol. 2010; 17: 457-463Crossref PubMed Scopus (105) Google Scholar, 5Scarabin PY Oger E Plu-Bureau G Differential association of oral and transdermal oestrogen-replacement therapy with venous thromboembolism risk.Lancet. 2003; 362: 428-432Summary Full Text Full Text PDF PubMed Scopus (666) Google Scholar In light of these data, the evidence for the implication of continuous oestrogen use in the increased risk of recurrent venous thrombosis should be modulated according to the route of oestrogen administration in postmenopausal women. We declare that we have no conflicts of interest. Risk assessment for recurrent venous thrombosis – Authors' replyIn a large case-control study from France, transdermal oestrogens did not increase the risk of a first venous thrombosis.1 Valérie Olié and co-workers now provide evidence that, by contrast with continued use of oral oestrogens, transdermal application of oestrogens after a first episode of venous thrombosis does not confer an increased risk of recurrence. However, we would still be hesitant to treat women with a history of venous thrombosis with transdermal oestrogens until more evidence is provided that this is safe. Full-Text PDF