title: Quality of INR control and outcomes following venous thromboembolism.
abstract: BACKGROUND
  The objective of this study was to evaluate the pattern of anticoagulation after venous thromboembolism (VTE) in actual clinical practice.
  
  
  METHODS
  This study used the General Practice Research Database. Individuals aged 18+ years with VTE were matched to 3 controls.
  
  
  RESULTS
  Of the 46 335 patients with VTE and 138 024 controls, 70.2% of cases and 86.6% of controls had no obvious risk factors. The mortality risk was increased substantially around the time of diagnosis (relative hazard rate [RR] around 21) but remained elevated for a further 4 years (RRs around 1.5-2.0). The mean percentage of time spent within the therapeutic range for international normalized ratio (INR) was 57.0%. The lowest rate of VTE recurrence occurred in patients with ≥70% time spent within therapeutic range (RR of 0.50, 95% CI 0.39-0.63 compared to <30%).
  
  
  CONCLUSIONS
  Higher time spent within therapeutic INR range was associated with lower risks of VTE recurrence and death due to VTE.
authors.affiliation: General Practice Research Database, Medicines and Healthcare products Regulatory Agency, London, UK.
authors.forename: Arlene M
authors.initials: AM
authors.lastname: Gallagher
authors.forename: Frank
authors.initials: F
authors.lastname: de Vries
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Plumb
authors.forename: Bastian
authors.initials: B
authors.lastname: Haß
authors.forename: Andreas
authors.initials: A
authors.lastname: Clemens
authors.forename: Tjeerd-Pieter
authors.initials: TP
authors.lastname: van Staa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage*; D016208:Databases, Factual; D005260:Female; D006801:Humans; D015994:Incidence; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013923:Thromboembolism / Q000188:drug therapy* / Q000401:mortality*; D006113:United Kingdom
chemical_list: D000925:Anticoagulants