title: Predictors of recurrence after deep vein thrombosis and pulmonary embolism: a population-based cohort study.
abstract: BACKGROUND
  The appropriate duration of oral anticoagulation after a first episode of venous thromboembolism (VTE) is uncertain and depends upon VTE recurrence rates.
  
  
  OBJECTIVE
  To estimate VTE recurrence rates and determine predictors of recurrence.
  
  
  METHODS
  Patients in Olmsted County, Minnesota, with a first lifetime deep vein thrombosis or pulmonary embolism diagnosed during the 25-year period from 1966 through 1990 (N = 1,719) were followed forward in time through their complete medical records in the community for first VTE recurrence.
  
  
  RESULTS
  Four hundred four patients developed recurrent VTE during 10,198 person-years of follow-up. The overall (probable/definite) cumulative percentages 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%), respectively. The risk of recurrence was greatest in the first 6 to 12 months after the initial event but never fell to zero. Independent predictors of first overall VTE recurrence included increasing age and body mass index, neurologic disease with paresis, malignant neoplasm, and neurosurgery during the period from 1966 through 1980. Independent predictors of first probable/definite recurrence included diagnostic certainty of the incident event and neurologic disease in patients with hospital-acquired VTE. Recurrence risk was increased by malignant neoplasm but varied with concomitant chemotherapy, patient age and sex, and study year.
  
  
  CONCLUSIONS
  Venous thromboembolism recurs frequently, especially within the 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 with malignant neoplasm are at increased risk for recurrence, while VTE patients with transient or reversible risk factors are at less risk.
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic and Mayo Foundation, Rochester, Minn 55905, USA. heit.john@mayo.edu
authors.forename: J A
authors.initials: JA
authors.lastname: Heit
authors.forename: D N
authors.initials: DN
authors.lastname: Mohr
authors.forename: M D
authors.initials: MD
authors.lastname: Silverstein
authors.forename: T M
authors.initials: TM
authors.lastname: Petterson
authors.forename: W M
authors.initials: WM
authors.lastname: O'Fallon
authors.forename: L J
authors.initials: LJ
authors.lastname: Melton
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011655:Pulmonary Embolism / Q000150:complications*; D012008:Recurrence; D012306:Risk; D012307:Risk Factors; D020246:Venous Thrombosis / Q000453:epidemiology / Q000209:etiology*