Recurrence risk of venous thromboembolism and hormone use in women from England: a cohort study using clinical practice research datalink.

Sylvia Kiconco,Alyshah Abdul Sultan,Matthew J Grainge

doi:10.1111/bjh.14516

Sylvia Kiconco, Alyshah Abdul Sultan + Show 1 more

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https://doi.org/10.1111/bjh.14516

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Abstract

It is vital to identify people with low recurrence risk of venous thromboembolism (VTE) so as to protect them from dangers of prolonged anticoagulation therapy. Among women who develop VTE following hormone use, the evidence as to whether their risk of recurrence is low if they cease this therapy is conflicting. We investigated whether women whose initial VTE event was hormone-related have a lower risk of VTE recurrence than women whose initial event had no obvious cause (unprovoked). A cohort study utilising the Clinical Practice Research Datalink linked to Hospital Episode Statistics data from England was conducted. We selected 4170 women aged between 15 and 64years who were diagnosed with a first VTE event between 1997 and 2011. Cox regression models were used to obtain hazard ratios (HR). Hormone users had 29% lower recurrence risk than non-users (adjusted HR=0·71; 95% confidence interval 0·58-0·88), a relationship which existed both in women aged 15-44years (predominantly oral contraceptive users) and those aged 45-64years (predominantly hormone replacement therapy users). In conclusion, having a hormone-associated VTE is associated with a lower recurrence risk than one that is unprovoked after discontinuation of the hormone-containing preparation. Prolonged anticoagulation may therefore be unjustified in such women.

Highlights

The incidence rate of venous thromboembolism (VTE) is estimated to be 1 to 2 per 1000 person years, and it is the third most common cause of cardiovascular death after coronary heart disease and stroke (Anderson et al, 1991; Silverstein et al, 1998; Cushman M et al, 2004; Tagalakis et al, 2013; Raskob et al, 2014)
One large US population based study (Heit et al, 2000) comprising 1,244 participants reported a 42% lower VTE recurrence risk in users than non-users of OCs in an unadjusted analysis and a much earlier UK study (Badaracco and Vessey, 1974) reported significantly lower proportion of VTE recurrences in OC users than in non-users. This supports a finding from a secondary analysis of pooled data from seven separate cohorts which reported that women with a hormone-associated VTE had a 50% lower risk of VTE recurrence than those who’s initial VTE had no obvious cause (Douketis et al, 2011) and that hormone use at baseline was found to be an independent term in a subsequent risk calculator using the same studies (Tosetto et al, 2012)
As a secondary hypothesis we explored whether re-initiation of hormone use during the follow-up period increased the risk of VTE recurrence

Summary

Introduction

The incidence rate of venous thromboembolism (VTE) is estimated to be 1 to 2 per 1000 person years, and it is the third most common cause of cardiovascular death after coronary heart disease and stroke (Anderson et al, 1991; Silverstein et al, 1998; Cushman M et al, 2004; Tagalakis et al, 2013; Raskob et al, 2014). One large US population based study (Heit et al, 2000) comprising 1,244 participants reported a 42% lower VTE recurrence risk in users than non-users of OCs in an unadjusted analysis and a much earlier UK study (Badaracco and Vessey, 1974) reported significantly lower proportion of VTE recurrences in OC users than in non-users This supports a finding from a secondary analysis of pooled data from seven separate cohorts which reported that women with a hormone-associated VTE had a 50% lower risk of VTE recurrence than those who’s initial VTE had no obvious cause (Douketis et al, 2011) and that hormone use at baseline was found to be an independent term in a subsequent risk calculator using the same studies (Tosetto et al, 2012). Several smaller studies which primarily addressed this hypothesis (Kyrle et al, 2004; Christiansen et al, 2005; Cushman et al, 2006; Le Gal et al, 2010; Le Moigne et al, 2013) reported no significant difference in the risk of VTE recurrence between women whose VTE was hormone related and women whose VTE was unprovoked

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