Predictors of recurrence after deep vein thrombosis and pulmonary embolism- A population-based cohort study

Background: The appropriate duration of oral anticoagulation after a first episode of venous thromboembolism (VTE) is uncertain and depends upon VTE r ecurrence rates. Objective: To estimate VTE recurrence rates and determine predictors of rec urrence. Methods: Patients in Olmsted County, Minnesota, with a first lifetime deep vein thrombosis or pulmonary embolism diagnosed during the 25-year period f rom 1966 through 1990 (N = 1719) were followed forward in time through thei r complete medical records in the community for first VTE recurrence. Results: Four hundred four patients developed recurrent VTE during 10 198 p erson-years of follow-up. The overall (probable/definite) cumulative percen tages of VTE recurrence at 7, 30, and 180 days and 1 and 10 years were 1.6% (0.2%), 5.2% (1.4%), 10.1% (4.1%), 12.9% (5.6%), and 30.4% (17.6%), respec tively. The risk of recurrence was greatest in the first 6 to 12 months aft er the initial event but never fell to zero. Independent predictors of firs t overall VTE recurrence included increasing age and body mass index, neuro logic disease with paresis, malignant neoplasm, and neurosurgery during the period from 1966 through 1980. Independent predictors of first probable/de finite recurrence included diagnostic certainty of the incident event and n eurologic disease in patients with hospital-acquired VTE. Recurrence risk w as increased by malignant neoplasm but varied with concomitant chemotherapy , patient age and sex, and study year. Conclusions: Venous thromboembolism recurs frequently, especially within th e first 6 to 12 months, and continues to recur for at least 10 years after the initial VTE. Patients with VTE with neurologic disease and paresis or w ith malignant neoplasm are at increased risk for recurrence, while VTE pati ents with transient or reversible risk factors are at less risk.