title: Warfarin treatment and risk of stroke among primary care patients with atrial fibrillation.
abstract: OBJECTIVE
  Our aim was to study the risk of a first ischaemic stroke (IS) in patients with atrial fibrillation (AF) treated in primary healthcare.
  
  
  METHODS
  The study population included all adults (n = 11,517), 45 years and older diagnosed with AF, from 75 primary care centres in Sweden between 2001 and 2007. IS was defined as a hospital care event of stroke between 2001 and 2010. Association between incident stroke and warfarin treatment was explored using Cox regression analysis, with hazard ratios (HRs), and 95% confidence intervals (95%CIs). Adjustment was made for age, socioeconomic factors and co-morbidity.
  
  
  RESULTS
  Persistent treatment with warfarin was present among 33.7% of women and 40.0% among men. Persistent warfarin treatment, compared to no persistent treatment, was associated with a stroke preventing effect with fully adjusted HRs of 0.25 (95%CI 0.18-0.36) in women, and 0.25 (95%CI 0.19-0.32) in men. A CHA2DS2-VASc score of at least two among women, and three among men, was associated with a stroke risk exceeding 18% during a mean follow-up of 5.4 years. Risk of haemorrhagic stroke was not increased.
  
  
  CONCLUSIONS
  Warfarin is effective in preventing stroke in AF patients in primary healthcare.
authors.affiliation: a Division of Family Medicine, Department of Neurobiology, Care Science and Society , Karolinska Institutet , Huddinge , Sweden.|b Academic Primary Healthcare Centre, Stockholm County Council , Huddinge , Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Wändell
authors.affiliation: a Division of Family Medicine, Department of Neurobiology, Care Science and Society , Karolinska Institutet , Huddinge , Sweden.|c Department of Medical Sciences , Cardiovascular Epidemiology, Uppsala University , Uppsala , Sweden.
authors.forename: Axel C
authors.initials: AC
authors.lastname: Carlsson
authors.affiliation: d Department of Emergency Medicine , Karolinska University Hospital , Stockholm , Sweden.|e Department of Internal Medicine , Karolinska Institutet , Stockholm , Sweden.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Holzmann
authors.affiliation: c Department of Medical Sciences , Cardiovascular Epidemiology, Uppsala University , Uppsala , Sweden.|f School of Health and Social Studies , Dalarna University , Falun , Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Ärnlöv
authors.affiliation: g Center for Primary Health Care Research, Lund University , Malmö , Sweden.
authors.forename: Sven-Erik
authors.initials: SE
authors.lastname: Johansson
authors.affiliation: g Center for Primary Health Care Research, Lund University , Malmö , Sweden.
authors.forename: Jan
authors.initials: J
authors.lastname: Sundquist
authors.affiliation: g Center for Primary Health Care Research, Lund University , Malmö , Sweden.
authors.forename: Kristina
authors.initials: K
authors.lastname: Sundquist
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D015897:Comorbidity; D005260:Female; D054625:Healthcare Disparities; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care; D016016:Proportional Hazards Models; D065840:Protective Factors; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D012959:Socioeconomic Factors; D020521:Stroke / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors; D016896:Treatment Outcome; D014859:Warfarin / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D014859:Warfarin
keywords: Atrial fibrillation; anticoagulant; co-morbidity; follow-up; gender; ischaemic stroke