Venous Thromboembolism in Older Adults: A Community-Based Study
What are the characteristics, treatment choices, and outcomes associated with venous thromboembolism (VTE) in older patients?
Older adults (≥65 years) with a diagnosis of VTE at one of six medical centers between 2008 and 2011 were examined. The primary outcomes included the incidence and risk of recurrent VTE, major bleeding, and all-cause mortality. Length of treatment with warfarin or low molecular weight heparin was recorded. Risk of VTE recurrence, major bleeding, and mortality was assessed in a multivariate model for patients ≥80 years versus <80 years of age.
A total of 1,223 older patients developed an index VTE during the study period. Older patients were more likely to be female, have suffered a recent fracture or heart failure, or to have a hospital-associated VTE. Malignancy-associated VTE occurred in 26% of the patients. Among patients with prior hospitalization (within 3 months of VTE), 22.2% had received no VTE prophylaxis and 4.9% received mechanical prophylaxis alone. Of all patients who survived at least 3 months after hospital discharge, the median duration of warfarin therapy was 351 days, with a shorter duration in provoked patients (203 days) compared to either unprovoked patients (401 days) or patients with malignancy-associated VTE (529 days). VTE recurrence rates were 3.0%, 7.8%, and 9.5%, respectively, at 30 days, 1 year, and 3 years of follow-up. The rate of recurrence did not differ based on patient age, including when adjusted for numerous recurrence risk factors. Major bleeding rates were 5.2%, 9.0%, and 10.6%, respectively, at 30 days, 1 year, and 3 years of follow-up. Age ≥80 years was associated with a trend toward increased bleeding risk (hazard ratio [HR], 1.42; 95% confidence interval [CI], 0.98-2.07) compared to younger patients. All-cause mortality rates were 9.9%, 28.4%, and 37.0%, respectively, for 30 days, 1 year, and 3 years of follow-up. Patients ≥80 years of age had an increased mortality risk (HR, 1.74; 95% CI, 1.43-2.11) compared to younger patients.
The authors concluded that older patients did not have an increased risk of recurrent VTE, but did have an increased risk of mortality and a trend toward increased risk of major bleeding. They also concluded that a high portion of patients with hospital-associated VTE did not receive adequate prophylaxis against VTE. Last, they concluded that many elderly patients with provoked VTE were receiving warfarin therapy for a greater period of time than recommended by current guideline recommendations.
This analysis highlights a number of important findings about VTE in the community setting. First, elderly patients were not shown to be at risk of VTE recurrence despite demonstrating a trend toward increased risk of major bleeding. However, malignancy-associated VTE is common in this population. Second, guideline-based therapy to prevent and treat VTE has opportunities for improvement, particularly in the prophylaxis against VTE for hospitalized patients and the length of therapy in patients with clearly provoked VTE. Quality improvement efforts focused on these two measures may help to reduce the burden of VTE and minimize the risk of anticoagulation-associated bleeding. This study did not include patients treated with the newer nonvitamin K oral antagonists. Assessing the impact these newer drugs have on VTE treatment patterns and outcomes, particularly in older patients, will be important to assess in the future.
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