title: Evaluation of time in therapeutic range in anticoagulated patients: a single-center, retrospective, observational study.
abstract: BACKGROUND
  The percentage of time during which the patients have the INR within the target values (i.e. Time in Therapeutic Range [TTR]) is a measure of anticoagulation quality with Vitamin K Antagonists (VKA). To evaluate the quality of anticoagulation using TTR according to the Rosendaal method, we performed an observational, retrospective study. We included all outpatients who attended the cardiology anticoagulation clinic of a Portuguese hospital (2011-2013), whose target INR was 2.0-3.0.
  
  
  RESULTS
  377 VKA-treated patients were evaluated. Of these, 72.4% had non-valvular atrial fibrillation. Patients were followed for a mean period of 471 days. The mean TTR was 60.3% (SD 19.3%) and 44.3% of the patients had a mean TTR<60%. Patients were at high risk of bleeding (INR>4.5) and at high thrombotic risk (INR<1.5) during, respectively, 1.7% and 4.7% of the time.
  
  
  CONCLUSIONS
  Anticoagulation control needs to be improved. These results are informative for all stakeholders: patients, health care professionals, and policymakers.
authors.affiliation: Cardiology Department, Hospital Garcia de Orta, Serviço de Cardiologia, Av,Torrado da Silva, 2805-267 Almada, Portugal. dgcaldeira@hotmail.com.
authors.forename: Daniel
authors.initials: D
authors.lastname: Caldeira
authors.forename: Inês
authors.initials: I
authors.lastname: Cruz
authors.forename: Gonçalo
authors.initials: G
authors.lastname: Morgado
authors.forename: Bruno
authors.initials: B
authors.lastname: Stuart
authors.forename: Catarina
authors.initials: C
authors.lastname: Gomes
authors.forename: Cristina
authors.initials: C
authors.lastname: Martins
authors.forename: Isabel
authors.initials: I
authors.lastname: João
authors.forename: Hélder
authors.initials: H
authors.lastname: Pereira
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006470:Hemorrhage / Q000517:prevention & control; D006761:Hospitals; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D011720:Pyrazoles / Q000627:therapeutic use*; D011728:Pyridones / Q000627:therapeutic use*; D012189:Retrospective Studies; D012307:Risk Factors; D000069552:Rivaroxaban / Q000627:therapeutic use*; D013997:Time Factors; D054556:Venous Thromboembolism / Q000188:drug therapy* / Q000503:physiopathology; D014859:Warfarin / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D011720:Pyrazoles; D011728:Pyridones; C522181:apixaban; D014859:Warfarin; D000069552:Rivaroxaban