title: History of thyroid disorders in relation to clinical outcomes in atrial fibrillation.
abstract: BACKGROUND
  Atrial fibrillation is the most common cardiac complication of hyperthyroidism. The association between history of hyperthyroidism and stroke remains unclear. We sought to determine whether history of thyroid dysfunction is a thromboembolic risk factor in patients with atrial fibrillation.
  
  
  METHODS
  Patients with atrial fibrillation seen in an academic institution between 2000 and 2010 were identified and followed-up. Clinical events (stroke/systemic embolism, bleeding, all-cause death) were recorded and related to thyroid status and disorders. Associations were examined in time-dependent models with adjustment for relevant confounders.
  
  
  RESULTS
  Among 8962 patients, 141 patients had a history of hyperthyroidism, 540 had a history of hypothyroidism, and 8271 had no thyroid dysfunction. Mean follow-up was 929 ± 1082 days. A total of 715 strokes/systemic embolism were recorded, with no significant difference in the rates of these events in patients with a history of thyroid dysfunction vs those without thyroid problems in either univariate or multivariable analysis (hazard ratio [HR] 0.85; 95% confidence interval [CI], 0.41-1.76 for hyperthyroidism; HR 0.98; 95% CI, 0.73-1.34 for hypothyroidism). There were 791 bleeding events; history of hypothyroidism was independently related to a higher rate of bleeding events (HR 1.35; 95% CI, 1.02-1.79). No significant difference among the 3 groups was observed for the incidence of death.
  
  
  CONCLUSIONS
  History of hyperthyroidism was not an independent risk factor for stroke/systemic embolism in atrial fibrillation, whereas hypothyroidism was associated with a higher risk of bleeding events. These data suggest no additional benefit from the inclusion of thyroid dysfunction in thromboembolic prediction models in atrial fibrillation.
authors: Service de Cardiologie, Centre Hospitalier Universitaire Trousseau et Faculté de Médecine, Université François Rabelais, Tours, France.
authors: Helene
authors: H
authors: Bruere
authors: Service de Cardiologie, Centre Hospitalier Universitaire Trousseau et Faculté de Médecine, Université François Rabelais, Tours, France. Electronic address: lfau@med.univ-tours.fr.
authors: Laurent
authors: L
authors: Fauchier
authors: Service de Cardiologie, Centre Hospitalier Universitaire Trousseau et Faculté de Médecine, Université François Rabelais, Tours, France.
authors: Anne
authors: A
authors: Bernard Brunet
authors: Service de Cardiologie, Centre Hospitalier Universitaire Trousseau et Faculté de Médecine, Université François Rabelais, Tours, France.
authors: Bertrand
authors: B
authors: Pierre
authors: Service de Cardiologie, Centre Hospitalier Universitaire Trousseau et Faculté de Médecine, Université François Rabelais, Tours, France.
authors: Edouard
authors: E
authors: Simeon
authors: Service de Cardiologie, Centre Hospitalier Universitaire Trousseau et Faculté de Médecine, Université François Rabelais, Tours, France.
authors: Dominique
authors: D
authors: Babuty
authors: Service de Cardiologie, Centre Hospitalier Universitaire Trousseau et Faculté de Médecine, Université François Rabelais, Tours, France.
authors: Nicolas
authors: N
authors: Clementy
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000150:complications* / Q000401:mortality; D005260:Female; D005602:France / Q000453:epidemiology; D006470:Hemorrhage / Q000209:etiology*; D006801:Humans; D006980:Hyperthyroidism / Q000150:complications*; D007037:Hypothyroidism / Q000150:complications*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D020521:Stroke / Q000209:etiology*; D013923:Thromboembolism / Q000209:etiology*
keywords: Atrial fibrillation; Hyperthyroidism; Hypothyroidism; Stroke