Background: Anticoagulation for at-risk medical populations for posthospitalization thromboprophylaxis has been investigated in previous studies demonstrating a benefit in reducing risk of asymptomatic deep-vein thrombosis (DVT) development, but no studies have examined symptomatic DVTs.
Study design: Randomized, double-blind, placebo-controlled, multinational clinical trial.
Setting: 671 multinational hospitals.
Synopsis: 11,962 patients were identified as at-risk patients based on length of hospitalization (3-10 days), diagnosis, and additional risk factors identified by anrisk score of greater than 4 or 2-3 with a D-dimer level more than twice the upper limit of normal. Patients were randomly assigned to receive rivaroxaban or placebo for 45 days. Primary outcome was composite of any symptomatic DVT or death related to VTE. Safety outcomes were principally related to bleeding. Symptomatic VTE or death from VTE occurred in 0.83% in the anticoagulation group and 1.1% in the placebo group (95% confidence interval, 0.52-1.09; P = .14). No significant difference was found in safety outcomes. The major limitation of the study was the low incidence of VTE and the need to include lower-risk patients (IMPROVE score 2/3 with elevated D-dimer), which may have decreased the effect of anticoagulation in the high-risk group (IMPROVE score 4 or greater).
Bottom line: No significant improvement in symptomatic VTE complications was found with posthospitalization thromboprophylaxis using rivaroxaban for an at-risk medical population.
Citation: Spyropoulos AC et al. Rivaroxaban for thromboprophylaxis after hospitalization for medical illness..
Dr. Imber is an assistant professor in the division of hospital medicine, University of New Mexico.