Recurrence risk after anticoagulant treatment of limited duration for late, second venous thromboembolism

Abstract

Patients with a second venous thromboembolism generally receive anticoagulant treatment indefinitely, although it is known that the recurrence risk diminishes over time while the risk of hemorrhage persists with continued anticoagulation and increases with age. Based on these arguments and limited evidence for indefinitely prolonged treatment, the Dutch guidelines recommend considering treatment of a limited duration (i.e. 12 months) for a 'late' second venous thromboembolism, defined by a second venous thromboembolism diagnosed more than 1 year after discontinuing treatment for a first event. It is hypothesized that the risk of continued anticoagulation might outweigh the benefits in such circumstances. We evaluated this management in daily practice. Since 2003, limited duration of treatment was systematically considered at our hospital in consecutive patients, in whom we determined the recurrence risk. Of 131 patients with late second venous thromboembolism, 77 were treated for a limited duration, of whom 26 developed a symptomatic third venous thromboembolism thereafter during a cumulative follow-up of 277 years, resulting in an incidence rate of 9.4/100 patient-years (95% confidence interval: 6.1-14). The incidence rates in patients with unprovoked and provoked venous thromboembolism were 12/100 patient-years (95% confidence interval: 7.4-19) and 5.6/100 patient-years (95% confidence interval: 2.2-12), respectively [adjusted hazard ratio 2.8 (95% confidence interval: 1.1-7.2)]. The recurrence risk after treatment of limited duration for 'late' second venous thromboembolism exceeded the risk of hemorrhage associated with extended anticoagulation. Most patients may, therefore, be better served by treatment of indefinite duration, although the risk-benefit ratio of extended anticoagulation should be weighed for every patient.

Copyright© Ferrata Storti Foundation.

Figures

Figure 1.

Cumulative incidence rate of a third venous thromboembolism in patients treated for a limited duration and patients treated for an indefinite duration. Follow-up started at the time of diagnosis of the second venous thromboembolism for both categories. nrVTE: number of recurrent VTE; PAR: patients at risk.

Figure 2.

Cumulative incidence rate of a third venous thromboembolism in patients with a provoked second VTE or an unprovoked second VTE, treated for a maximum of 12 months. Follow-up started at the time of cessation of anticoagulant treatment. nrVTE: number of recurrent VTE; PAR: patients at risk.