title: Bleeding complications during warfarin treatment in primary healthcare centres compared with anticoagulation clinics.
abstract: OBJECTIVE
  To examine determinants of bleeding complications during warfarin treatment in an unselected patient population and evaluate possible differences in safety between specialized anticoagulation clinics and primary healthcare centres.
  
  
  METHODS
  Prospective cohort study. Data were collected with an admission form and medical records were scrutinized in order to pursue all adverse events. Differences between groups were estimated with a t-test and chi-squared test, and univariate and multivariate Cox regression analysis.
  
  
  METHODS
  All patients treated and monitored with oral anticoagulation in primary healthcare centres and specialized anticoagulation clinics in the Sundsvall and Skellefteå region (northern Sweden) during a five-year period.
  
  
  METHODS
  A total of 2731 patients corresponding to 5044 treatment years.
  
  
  METHODS
  Bleedings were classified as fatal or major. Major bleedings were defined as an event causing admission, prolonged in-hospital care or death.
  
  
  RESULTS
  In total 195 major bleedings occurred corresponding to 3.9% per treatment year, including 34 fatal events (0.67% per treatment year). Patients monitored at the two specialized anticoagulation clinics combined had a major bleeding frequency of 4.1% as compared with 3.9% at primary healthcare units. The frequency of fatal haemorrhage was 0.57% and 0.76%, respectively. The rate of major and fatal bleeding was age related with an increase of 4% and 5%, respectively, per year.
  
  
  CONCLUSIONS
  There was no difference in bleeding complications between patients monitored at primary healthcare centres and specialized anticoagulation clinics. Age was continuously and independently associated with bleeding risk. These study data indicate the need to exercise caution in treatment of the elderly.
authors.affiliation: Division of Hematology, Department of Medicine at Sundsvall Hospital, Sundsvall, Sweden. jonas.wallvik@lvn.se
authors.forename: Jonas
authors.initials: J
authors.lastname: Wallvik
authors.forename: Anders
authors.initials: A
authors.lastname: Själander
authors.forename: Lars
authors.initials: L
authors.lastname: Johansson
authors.forename: Orjan
authors.initials: O
authors.lastname: Bjuhr
authors.forename: Jan-Håkan
authors.initials: JH
authors.lastname: Jansson
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects*; D015331:Cohort Studies; D005194:Family Practice; D005500:Follow-Up Studies; D006470:Hemorrhage / Q000139:chemically induced*; D006801:Humans; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011320:Primary Health Care; D011446:Prospective Studies; D012307:Risk Factors; D012449:Safety; D014859:Warfarin / Q000009:adverse effects*
chemical_list: D000925:Anticoagulants; D014859:Warfarin