Predictors and outcomes of recurrent venous thromboembolism in elderly patients

Abstract

BACKGROUND: Little is known about predictors and outcomes of recurrent venous thromboembolism in elderly patients.
METHODS: We prospectively followed up 991 patients aged ≥65 years with acute venous thromboembolism in a multicenter Swiss cohort study. The primary outcome was symptomatic recurrent venous thromboembolism. We explored the association between baseline characteristics and treatments and recurrent venous thromboembolism using competing risk regression, adjusting for periods of anticoagulation as a time-varying co-variate. We also assessed the clinical consequences (case-fatality, localization) of recurrent venous thromboembolism.
RESULTS: During a median follow-up period of 30 months, 122 patients developed recurrent venous thromboembolism, corresponding to a 3-year cumulative incidence of 14.8%. The case-fatality of recurrence was high (20.5%), particularly in patients with unprovoked (23%) and cancer-related venous thromboembolism (29%). After adjustment, only unprovoked venous thromboembolism (sub-hazard ratio [SHR] 1.67 compared to provoked venous thromboembolism; 95% confidence interval [CI] 1.00-2.77) and proximal deep vein thrombosis (SHR 2.41 compared to isolated distal deep vein thrombosis; 95% CI 1.07-5.38) were significantly associated with recurrence. Patients with initial pulmonary embolism were more likely to have another pulmonary embolism as a recurrent event than patients with deep vein thrombosis.
CONCLUSIONS: Elderly patients with acute venous thromboembolism have a substantial long-term risk of recurrent venous thromboembolism and recurrence carries a high case-fatality rate. Only two factors, unprovoked venous thromboembolism and proximal deep vein thrombosis, were independently associated with recurrent venous thromboembolism, indicating that traditional risk factors for venous thromboembolism recurrence (e.g., cancer) may be less relevant in the elderly.