Weekly risk of venous thromboembolism recurrence in patients receiving oral anticoagulants

BACKGROUND: Data is currently lacking in evaluating the weekly rates of recurrent venous thromboembolism (VTE) among patients receiving anticoagulants. OBJECTIVE: To quantify the risk of VTE recurrence during the first 12 weeks after an index VTE event. METHODS: Healthcare claims from Truven Health Analytics MarketScan database from January 2007 to June 2012 were analyzed. Adult patients with ≥1 diagnosis of VTE, ≥1 anticoagulant prescription dispensed within 7 days of the index VTE hospitalization discharge or outpatient/emergency room (ER) visit (index date), and a proportion of days covered ≥0.7 on the anticoagulant therapy during the 12 weeks post-discharge were included. The weekly risk of VTE recurrence was evaluated with the hazard function using the life-table method. RESULTS: A total of 105,682 patients with a VTE were included. Mean age was 59 years and 49% were female. The risk of VTE recurrence was at its highest during the first and second weeks, at 0.78% and 0.83%, respectively. The risk remained high during Weeks 3, 4, and 5 with risks of VTE recurrence of 0.63%, 0.52%, and 0.39%, respectively. The risk of VTE recurrence stabilized around Week 7, with risks of 0.26%, 0.22%, 0.20%, 0.25%, 0.23%, and 0.23% for Weeks 7, 8, 9, 10, 11 and 12, respectively. LIMITATIONS: Claims data may have contained inaccuracies. During hospitalizations it was not possible to assess anticoagulant use or a VTE recurrence occurring in the same hospitalization as the index VTE event. CONCLUSION: This analysis suggests that the risk of VTE recurrence remains high in the early weeks after an index VTE among patients receiving anticoagulants.