PATTERNS AND PREDICTORS OF USE OF ANTICOAGULANTS FOR ACUTE VENOUS THROMBOEMBOLISM

Abstract

Few studies have identified patterns and predictors of use of novel oral anticoagulants compared to warfarin for acute venous thromboembolism (VTE) in clinical practice. To describe the use of anticoagulants (AC) and to identify patient’s characteristics associated with the choice of rivaroxaban over warfarin for the treatment of VTE. A retrospective cohort was built from outpatient visits and inpatients records of hospitalisation between February 18, 2013, and September 18, 2013 (ie. starting 2 months following the availability of rivaroxaban for the treatment of VTE at our institution). This cohort includes new AC’s users treated in a tertiary care center for VTE. General characteristics and the type of AC prescribed was described using means and proportions and predictors of use of novel AC were analysed using two-tailed Student’s t-test for continuous variables and chi-square test for categorical variables. In an 8-months period, 261 patients were included; 67 (26%) had a diagnosis of cancer, 52 (20%) had at least one previous episode of VTE and 17 (7%) had confirm inherited thrombophilia. The median age was 65 years and 52% of the patients were women. The median body mass index was 28 (data were available for 199 patients) and the median length of stay was 8 days for hospitalisation (118 patients). Overall, 146 (56%) received warfarin, 43 (16%) received rivaroxaban and 72 (28%) received a prescription for long-term low molecular weight heparin at discharge. When compared to patients on warfarin, those who received rivaroxaban at discharge were younger (53 versus 63 years, p=0,001), had a higher mean creatinine clearance (93 versus 79 mL/min, p=0,002), were more likely to have an ambulatory visit rather than a hospitalisation (31% versus 60%, p<0,001) and were more likely to have a deep venous thrombosis than a pulmonary embolism (36% versus 58%, p=0,011). In new users of oral anticoagulants for the management of VTE, more subjects were on warfarin. Patients on rivaroxaban were younger and had a higher renal creatinine clearance. Rivaroxaban was more frequently prescribed in subjects who were not hosiptalized.