title: Effect of Diabetes and Glycemic Control on Ischemic Stroke Risk in AF Patients: ATRIA Study.
abstract: BACKGROUND
  Diagnosed diabetes mellitus (DM) is a consistently documented risk factor for ischemic stroke in patients with atrial fibrillation (AF).
  
  
  OBJECTIVE
  The purpose of this study was to assess the association between duration of diabetes and elevated hemoglobin A1c (HbA1c) with risk of stroke among diabetic patients with AF.
  
  
  METHODS
  We assessed this association in the ATRIA (Anticoagulation and Risk Factors in Atrial Fibrillation) California community-based cohort of AF patients (study years 1996 to 2003) where all events were clinician adjudicated. We used Cox proportional hazards regression to estimate the rate of ischemic stroke in diabetic patients according to time-varying measures of estimated duration of diabetes (≥3 years compared with <3 years) and HbA1c values (≥9.0% and 7.0% to 8.9% compared with <7.0%), focusing on periods where patients were not anticoagulated.
  
  
  RESULTS
  There were 2,101 diabetic patients included in the duration analysis: 40% with duration <3 years and 60% with duration ≥3 years at baseline. Among 1,933 diabetic patients included in the HbA1c analysis, 46% had HbA1c <7.0%, 36% between 7.0% and 8.9%, and 19% ≥9.0% at baseline. Duration of diabetes ≥3 years was associated with an increased rate of ischemic stroke compared with duration <3 years (adjusted hazard ratio [HR]: 1.74, 95% confidence interval [CI]: 1.10 to 2.76). The increased stroke rate was observed in older (age ≥75 years) and younger (age <75 years) individuals. Neither poor glycemic control (HbA1c ≥9.0%, adjusted HR: 1.04, 95% CI: 0.57 to 1.92) nor moderately increased HbA1c (7.0% to 8.9%, adjusted HR: 1.21, 95% CI: 0.77 to 1.91) were significantly associated with an increased rate of ischemic stroke compared with patients who had HbA1c <7.0%.
  
  
  CONCLUSIONS
  Duration of diabetes is a more important predictor of ischemic stroke than glycemic control in patients who have diabetes and AF.
authors.affiliation: Division of General Internal Medicine, Massachusetts General Hospital, Boston, Massachusetts; Harvard Medical School, Boston, Massachusetts; Epidemiology Department, Boston University School of Public Health, Boston, Massachusetts. Electronic address: jashburner@mgh.harvard.edu.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Ashburner
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, California; Department of Epidemiology, Biostatistics and Medicine, University of California, San Francisco, California; Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California.
authors.forename: Alan S
authors.initials: AS
authors.lastname: Go
authors.affiliation: Division of General Internal Medicine, Massachusetts General Hospital, Boston, Massachusetts; Harvard Medical School, Boston, Massachusetts.
authors.forename: Yuchiao
authors.initials: Y
authors.lastname: Chang
authors.affiliation: Department of Medicine, University of California, San Francisco, San Francisco, California.
authors.forename: Margaret C
authors.initials: MC
authors.lastname: Fang
authors.affiliation: Epidemiology Department, Boston University School of Public Health, Boston, Massachusetts.
authors.forename: Lisa
authors.initials: L
authors.lastname: Fredman
authors.affiliation: Department of Environmental and Occupational Health, School of Public Health and Health Services, The George Washington University, Washington, DC; Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts.
authors.forename: Katie M
authors.initials: KM
authors.lastname: Applebaum
authors.affiliation: Division of General Internal Medicine, Massachusetts General Hospital, Boston, Massachusetts; Harvard Medical School, Boston, Massachusetts.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Singer
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology; D001786:Blood Glucose / Q000032:analysis*; D002545:Brain Ischemia / Q000453:epidemiology / Q000209:etiology; D002140:California / Q000453:epidemiology; D015897:Comorbidity; D003920:Diabetes Mellitus / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology / Q000209:etiology
chemical_list: D000925:Anticoagulants; D001786:Blood Glucose; D006442:Glycated Hemoglobin
keywords: atrial fibrillation; diabetes mellitus; stroke