title: Comparison of prothrombin time (INR) results and main characteristics of patients on warfarin treatment in primary health care centers and anticoagulation clinics.
abstract: BACKGROUND
  Oral anticoagulant therapy is used to prevent thrombosis in patients with atrial fibrillation (AF), venous thrombosis and prosthetic heart valves. The introduction of new therapies emphasizes the need to discern the best practice for the patients remaining on warfarin treatment. This study compares patient characteristics and therapeutic control in two settings managing warfarin treatment: Swedish primary health care centers (PHCC) and specialized anticoagulation clinics (ACC).
  
  
  METHODS
  Prothrombin time (PT) test results reported as International Normalized Ratio (INR) were collected for five consecutive days from patients on warfarin treatment; 564 PHCC and 927 ACC patients. Therapeutic control was calculated as PT test results in relation to intended therapeutic range (TR). Mann-Whitney Rank Sum Test and Chi2 test were used for statistical comparisons.
  
  
  RESULTS
  The PHCC patients were older than the ACC patients, 76 v. 70 years (p<0.01) with a predominance of men in both groups. The reasons for treating differed between the groups. Seventy-two percent of PHCC patients and 66% of ACC patients had a PT-INR within the intended TR (p<0.05). Men generally had better results than women (72% v. 63%, p<0.001) and particularly in the PHCC group v. the ACC group (78% v. 69%, p<0.01).PT-INR above intended TR was significantly more common in the ACC setting, (p<0.05), for women overall (p<0.01), for women in the PHCC setting, and for ACC men (p<0.05).
  
  
  CONCLUSIONS
  In this study both settings achieved good therapeutic control of warfarin treatment with a minor advantage for PHCC over ACC, and better results for men, especially in the PHCC setting. As patient characteristics differ between the PHCC and ACC, it is important to conduct further randomized studies to discern the best practice locally for warfarin management also after the introduction of new drugs.
authors.affiliation: Department of Medical and Health Sciences, Linköping University, Department of Acute Internal Medicine, County Council of Östergötland, Linköping, S581 85, Sweden. kerstin.arbring@lio.se
authors.forename: Kerstin
authors.initials: K
authors.lastname: Arbring
authors.forename: Srinivas
authors.initials: S
authors.lastname: Uppugunduri
authors.forename: Tomas L
authors.initials: TL
authors.lastname: Lindahl
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000097:blood*; D003151:Community Health Centers; D003430:Cross-Sectional Studies; D016903:Drug Monitoring / Q000379:methods; D005260:Female; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D011320:Primary Health Care; D011517:Prothrombin Time / Q000379:methods*; D013548:Sweden; D016896:Treatment Outcome; D014859:Warfarin / Q000097:blood*
chemical_list: D000925:Anticoagulants; D014859:Warfarin