Index clinical manifestation of venous thromboembolism predicts early recurrence type and frequency: a meta-analysis of randomized controlled trials

BackgroundObservational studies suggest index clinical manifestation of venous thromboembolism (VTE) predicts recurrence type. Data regarding the association between index manifestation and recurrence rates are conflicting. ObjectivesTo perform a meta-analysis of randomized controlled trials (RCTs) to determine the type and frequency of recurrent VTE (rVTE) in persons after an index deep vein thrombosis (DVT) or pulmonary embolism (PE). Patients/MethodsWe searched bibliographic databases for RCTs of acute (early) treatment of rVTE in persons with an index DVT or PE (DVT), enrolling 50 subjects anticoagulated 3-months and reporting types of rVTE. We pooled (random-effects) the proportion of rVTEs that were DVTs, PEs, and fatal PEs, the proportion of recurrent PEs that were fatal, and absolute rVTE rates. ResultsIn nine RCTs (N=13640; 413 rVTEs) evaluating persons with an index PE; 66% (95% CI, 60-72%) of rVTEs were PE and 27% (95% CI, 22-33%) were fatal PE. Among 25 RCTs (N=17340; 692 rVTEs) evaluating persons with an index DVT, 36% (95% CI, 29-44%) experienced a recurrent PE and 10% (95% CI, 7-13%) a fatal PE. Recurrent PEs following an index PE had a higher fatality rate than after an index DVT (41%; 95% CI, 33-48% vs. 25%; 95% CI, 18-33%; P=0.007). The rVTE rate was higher following an index DVT compared with a PE (2.6%; 95% CI, 1.6-3.8% vs. 4.9%; 95% CI, 4.0-6.0%; P=0.002). ConclusionsOur meta-analysis suggests most rVTEs will be the same type as the index event. While index DVTs are associated with a higher rVTE rate than index PEs; recurrent PEs are associated with high fatality.