title: The 'obesity paradox' in atrial fibrillation: observations from the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial.
abstract: The prognostic implication of adiposity on clinical outcomes in atrial fibrillation (AF) patients treated with oral anticoagulation is unclear.
  
  
  
  A total of 17 913 patients in the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation trial had body mass index (BMI) measured at baseline. For the primary analysis, BMI was categorized as normal (18.5 to <25 kg/m2), overweight (25 to <30 kg/m2), and obese (≥30 kg/m2). Waist circumference (WC) was defined as high if >102 cm for men and >88 cm in women. Outcomes were stroke or systemic embolism, a composite endpoint (stroke, systemic embolism, myocardial infarction, or all-cause mortality), all-cause mortality, and major bleeding. Cox models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) across categories of BMI and WC adjusting for established risk factors and treatment allocation. At baseline, 4052 (22.6%) patients had a normal BMI, 6702 (37.4%) were overweight, and 7159 (40.0%) were obese. In multivariable analyses, higher BMI was associated with a lower risk of all-cause mortality [overweight: HR 0.67 (95% CI 0.59-0.78); obese: HR 0.63 (95% CI 0.54-0.74), P < 0.0001] and the composite endpoint [overweight: HR 0.74 (95% CI 0.65-0.84); obese: HR 0.68 (95% CI 0.60-0.78), P < 0.0001] compared with normal BMI. In women, high WC was associated with a 31% lower risk of all-cause mortality (P = 0.001), 27% lower risk of the composite endpoint (P = 0.001), and 28% lower risk of stroke or systemic embolism (P = 0.048) but not in men. There was no significant association between adiposity and major bleeding.
  
  
  
  In patients with AF treated with oral anticoagulants, higher BMI and WC are associated with a more favourable prognosis.
authors.affiliation: Mazankowski Alberta Heart Institute, University of Alberta, 8440-112 Street, 2C2 WMC, Edmonton, Alberta, Canada T6G 2B7 rsandhu2@ualberta.ca.
authors.forename: Roopinder K
authors.initials: RK
authors.lastname: Sandhu
authors.affiliation: Mazankowski Alberta Heart Institute, University of Alberta, 8440-112 Street, 2C2 WMC, Edmonton, Alberta, Canada T6G 2B7.|Canadian VIGOUR Centre, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Justin
authors.initials: J
authors.lastname: Ezekowitz
authors.affiliation: Uppsala Clinical Research Center, Uppsala University, Uppsala, Sweden.
authors.forename: Ulrika
authors.initials: U
authors.lastname: Andersson
authors.affiliation: Duke Clinical Research Institute, Duke Medicine, Durham, NC, USA.
authors.forename: John H
authors.initials: JH
authors.lastname: Alexander
authors.affiliation: Duke Clinical Research Institute, Duke Medicine, Durham, NC, USA.
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Granger
authors.affiliation: Department of Cardiology B, Oslo University Hospital Ulleval and University of Oslo, Oslo, Norway.
authors.forename: Sigrun
authors.initials: S
authors.lastname: Halvorsen
authors.affiliation: Bristol-Myers Squibb, Princeton, NJ, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Hanna
authors.affiliation: Uppsala Clinical Research Center, Uppsala University, Uppsala, Sweden.|Department of Medical Sciences, Cardiology, Uppsala University, Uppsala, Sweden.
authors.forename: Ziad
authors.initials: Z
authors.lastname: Hijazi
authors.affiliation: University Hospital Motol, Prague, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Jansky
authors.affiliation: Duke Clinical Research Institute, Duke Medicine, Durham, NC, USA.
authors.forename: Renato D
authors.initials: RD
authors.lastname: Lopes
authors.affiliation: Uppsala Clinical Research Center, Uppsala University, Uppsala, Sweden.|Department of Medical Sciences, Cardiology, Uppsala University, Uppsala, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Wallentin
mesh_terms: D000925:Anticoagulants; D001281:Atrial Fibrillation; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity; D011720:Pyrazoles; D011728:Pyridones; D020521:Stroke; D016896:Treatment Outcome; D014859:Warfarin
chemical_list: D000925:Anticoagulants; D011720:Pyrazoles; D011728:Pyridones; C522181:apixaban; D014859:Warfarin
keywords: Adiposity; Atrial fibrillation; Outcomes