title: Sex, age and normal post-anticoagulation D-dimer as risk factors for recurrence after idiopathic venous thromboembolism in the Prolong study extension.
abstract: BACKGROUND
  The PROLONG randomized study showed that patients with an abnormal D-dimer after anticoagulation suspension for a first unprovoked episode of venous thromboembolism (VTE) benefited from anticoagulation resumption. Patients with normal D-dimer after anticoagulation suspension had a low recurrence rate (4.4% patient-years) but their anticoagulation optimal duration remained uncertain.
  
  
  OBJECTIVE
  To assess whether sex and age, in combination with normal D-dimer, are risk factors for VTE recurrence in patients enrolled in the PROLONG study extended follow-up.
  
  
  METHODS
  D-dimer was measured at 1 month after anticoagulation suspension. Patients with a normal D-dimer did not resume anticoagulants, whereas patients with an abnormal D-dimer were randomized either to resume or not anticoagulants. Primary outcome was recurrent VTE.
  
  
  RESULTS
  After excluding patients resuming anticoagulants for abnormal D-dimer, recurrences were higher in males than females [7.4% patient-years - 47/639 vs. 4.3% patient-years - 27/626; hazard ratio (HR) = 1.7; P = 0.027] and in patients aged 65 or older than in younger patients (8.4% patient-years - 50/598 vs. 3.6% patient-years - 24/667; HR = 2.1; P = 0.003). In patients with normal D-dimer and younger than 65, recurrences were higher in males than in females (5.1% vs. 0.4% patient-years; adjusted HR = 10.6; P = 0.023) and both females and males aged 65 years or older had more recurrences (6.6% and 8.1% patient-years, respectively, adjusted HR: 16.0; P = .008 and 16.0; P = 0.008, respectively) than females younger than 65.
  
  
  CONCLUSIONS
  In patients with idiopathic VTE and a normal D-dimer at 1 month after anticoagulation suspension, females younger than 65 had a very low risk of recurrence.
authors.affiliation: Department of Angiology & Blood Coagulation Marino Golinelli, S.Orsola-Malpighi University Hospital, Bologna, Italy. benilde.cosmi@unibo.it
authors.forename: B
authors.initials: B
authors.lastname: Cosmi
authors.forename: C
authors.initials: C
authors.lastname: Legnani
authors.forename: A
authors.initials: A
authors.lastname: Tosetto
authors.forename: V
authors.initials: V
authors.lastname: Pengo
authors.forename: A
authors.initials: A
authors.lastname: Ghirarduzzi
authors.forename: S
authors.initials: S
authors.lastname: Testa
authors.forename: D
authors.initials: D
authors.lastname: Prisco
authors.forename: D
authors.initials: D
authors.lastname: Poli
authors.forename: A
authors.initials: A
authors.lastname: Tripodi
authors.forename: G
authors.initials: G
authors.lastname: Palareti
mesh_terms: D000367:Age Factors; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use*; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000627:therapeutic use*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012306:Risk; D012307:Risk Factors; D012737:Sex Factors; D013997:Time Factors; D016896:Treatment Outcome; D054556:Venous Thromboembolism / Q000097:blood* / Q000628:therapy*
chemical_list: D000925:Anticoagulants; D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D