Recurrent venous thromboembolism after pregnancy-associated versus unprovoked thromboembolism

Summary

It is not known whether women who develop venous throm-boembolism (VTE) during pregnancy have a higher or lower incidence of recurrent VTE than women with unprovokedVTE. The aim of the study was to compare the risk of recurrent VTE among women with pregnancy-associated VTE to women with unprovoked VTE. Hospital discharge data identified women age 18–46 years old with pregnancy-associated or unprovoked index VTE between 1994 and 2005. Risk of recurrent VTE was compared between six and 60 months after the index event using both age-matched comparison of disease-free survival and proportional hazard modelling, adjusting for age and other risk factors. The Kaplan-Meier incidence of recurrent VTE in 1085 women with pregnancy-associatedVTE was 5.8% versus 10.4% in 7625 women with unprovoked VTE (p=0.02). Twelve of 34 (35%) recurrent events in the pregnancy-associated group occurred during a subsequent pregnancy compared with 29 of 331 (8.7%) events in the unprovoked group (p<0.001).In the risk-adjusted multivariate model, women with pregnancy-associated VTE had a significantly lower risk of recurrent VTE (HR = 0.6, 95%CI=0.4–0.9). Overall, the incidence of recurrentVTE during subsequent pregnancies was higher in the pregnancy group, 21 of 465 (4.5%), than in the unprovoked group, 37 of 1353 (2.7%, RR=1.7, CI:1.0–2.8). Compared to women with unprovoked VTE, women with pregnancy-associated VTE had a significantly lower long-term risk of recurrent VTE but a higher risk of recurrent VTE during a subsequent pregnancy. These findings should be considered when decisions are made about VTE prophylaxis in women with a history of pregnancy-associated VTE.

Keywords

Venous thromboembolism - epidemiology - recurrent - pregnancy - unprovoked

• References

• 1 Research Committee of, the British, Thoracic Society. Optimum duration of anticoagulation for deepvein thrombosis and pulmonary embolism. Lancet 1992; 340: 873-876.
• 2 Hansson PO, Sörbo J, Eriksson H. Recurrent venous thromboembolism after deep vein thrombosis: incidence and risk factors. Arch Intern Med 2000; 160: 769-774.
• 3 Prandoni P, Lensing AW, Cogo A. et al. The long-term clinical course of acute deep venous thrombosis. Ann Intern Med 1996; 125: 1-7.
• 4 Schulman S, Rhedin AS, Lindmarker P. et al. A comparison of six weeks with six months of oral anticoagulant therapy after a first episode of venous throm-boembolism. Duration of Anticoagulation Trial Study Group. N Engl J Med 1995; 332: 1661-1665.
• 5 Levine MN, Hirsh J, Gent M. et al. Optimal duration of oral anticoagulant therapy: a randomized trial comparing four weeks with three months of warfarin in patients with proximal deep vein thrombosis. Thromb Haemost 1995; 74: 606-611.
• 6 Baglin T, Luddington R, Brown K. et al. Incidence of recurrent venous thromboembolism in relation to clinical and thrombophilic risk factors: prospective cohort study. Lancet 2003; 362: 523-526.
• 7 Palareti G, Cosmi B. Predicting the risk of recurrence of venous thromboembolism. Current opinion in hematology 2004; 11: 192-197.
• 8 Keeling D. Duration of anticoagulation: decision making based on absolute risk. Blood Rev. 2005 Nov 3..
• 9 Schulman S, Ogren M. New concepts in optimal management of anticoagulant therapy for extended treatment of venous thromboembolism. Thromb Hae-most 2006; Sep; 96: 258-266.
• 10 Bates SM, Greer IA, Hirsh J. et al. Use of anti-thrombotic agents during pregnancy: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest 2004; 126 (Suppl. 03) 627S-44S.
• 11 Ginsberg JS, Turpie AG. Thromboembolism and pregnancy. Int Angiol 2001; 20: 103-109.
• 12 Greer IA. Venous thromboembolism and anticoagulant therapy in pregnancy. Gend Med 2005; 02 Suppl A: S10-17.
• 13 Pabinger I, Grafenhofer H. Thrombosis during pregnancy: risk factors, diagnosis and treatment. Pathophysiol Haemost Thromb 2002; 32: 322-324.
• 14 White RH, Zhou H, Murin S. et al. Effect of ethnicity and gender on the incidence of venous thromboem-bolism in a diverse population in California in 1996. Thromb Haemost 2005; 93: 298-305.
• 15 White RH, Romano PS, Zhou H. et al. Incidence and time course of thromboembolic outcomes following total hip or knee arthroplasty. Arch Intern Med 1998; 158: 1525-1531.
• 16 White RH, Brickner LA, Scannell KA. ICD-9-CM codes poorly indentified venous thromboembolism during pregnancy. J Clin Epidemiol 2004; 57: 985-988.
• 17 American Hospital Association. Coding Clinic for ICD-9-CM. 2001 Quarter 01: 11-12.
• 18 Health Care Utilization Project. Comorbidity Software, Version 3.1. 2005 [updated 2005 Fiscal Year 2006; cited April 17, 2006]; Available at: http://www.hcup-us.ahrq.gov/toolssoftware/comorbidity/comorbidity.jsp
• 19 Stukenborg GJ, Wagner DP, Connors Jr AF. Comparison of the performance of two comorbidity measures, with and without information from prior hospitalizations. Med Care 2001; 39: 727-739.
• 20 Kearon C. Long-term management of patients after venous thromboembolism. Circulation 2004; 110 (Suppl. 09) I10-8.
• 21 Heit JA, Mohr DN, Silverstein MD. et al. Predictors of recurrence after deep vein thrombosis and pulmonary embolism: a population-based cohort study. Arch Int Med 2000; 160: 761-768.
• 22 De Stefano V, Martinelli I, Rossi E. et al. The risk of recurrent venous thromboembolism in pregnancy and puerperium without antithrombotic prophylaxis. B J Haematol 2006; 135: 386-391.
• 23 Ray JG, Chan WS. Deep vein thrombosis during pregnancy and the puerperium: a meta-analysis of the period of risk and the leg of presentation. Obstet Gynecol Surv 1999; 54: 265-271.
• 24 Buller HR, Agnelli G, Hull RD. et al. Antithrombotic Therapy for Venous Thromboembolic Disease: The Seventh ACCP Conference onAntithrombotic and Thrombolytic Therapy. Chest 2004; 126 (Suppl. 03) 401S-28.
• 25 Prandoni P, Noventa F, Ghirarduzzi A. et al. The risk of recurrent venous thromboembolism after discontinuing anticoagulation in patients with acute proximal deep vein thrombosis or pulmonary embolism A prospective cohort study in 1,626 patients. Haematologica 2007; 92: 199-205.