Warfarin, kidney dysfunction, and outcomes following acute myocardial infarction in patients with atrial fibrillation

JAMA. 2014 Mar 5;311(9):919-28. doi: 10.1001/jama.2014.1334.


Importance: Conflicting evidence exists regarding the association between warfarin treatment, death, and ischemic stroke incidence in patients with advanced chronic kidney disease (CKD) and atrial fibrillation.

Objective: To study outcomes associated with warfarin treatment in relation to kidney function among patients with established cardiovascular disease and atrial fibrillation.

Design, setting, and participants: Observational, prospective, multicenter cohort study from the Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies (SWEDEHEART) registry (2003-2010), which includes all Swedish hospitals that provide care for acute cardiac diseases. Participants included consecutive survivors of an acute myocardial infarction (MI) with atrial fibrillation and known serum creatinine (N = 24,317), including 21.8% who were prescribed warfarin at discharge. Chronic kidney disease stages were classified according to estimated glomerular filtration rate (eGFR).

Main outcomes and measures: (1) Composite end point analysis of death, readmission due to MI, or ischemic stroke; (2) bleeding (composite of readmission due to hemorrhagic stroke, gastrointestinal bleeding, bleeding causing anemia, and others); or (3) the aggregate of these 2 outcomes within 1 year from discharge date.

Results: A total of 5292 patients (21.8%) were treated with warfarin at discharge, and 51.7% had manifest CKD (eGFR <60 mL/min/1.73 m2 [eGFR<60]). Compared with no warfarin use, warfarin was associated with a lower risk of the first composite outcome (n = 9002 events) in each CKD stratum for event rates per 100 person-years: eGFR>60 event rate, 28.0 for warfarin vs 36.1 for no warfarin; adjusted hazard ratio (HR), 0.73 (95% CI, 0.65 to 0.81); eGFR>30-60: event rate, 48.5 for warfarin vs 63.8 for no warfarin; HR, 0.73 (95% CI, 0.66 to 0.80); eGFR>15-30: event rate, 84.3 for warfarin vs 110.1 for no warfarin; HR, 0.84 (95% CI, 0.70-1.02); eGFR≤15: event rate, 83.2 for warfarin vs 128.3 for no warfarin; HR, 0.57 (95% CI, 0.37-0.86). The risk of bleeding (n = 1202 events) was not significantly higher in patients treated with warfarin in any CKD stratum for event rates per 100 person-years: eGFR>60 event rate, 5.0 for warfarin vs 4.8 for no warfarin; HR, 1.10 (95% CI, 0.86-1.41); eGFR>30-60 event rate, 6.8 for warfarin vs 6.3 for no warfarin; HR, 1.04 (95% CI, 0.81-1.33); eGFR>15-30 event rate, 9.3 for warfarin vs 10.4 for no warfarin; HR, 0.82 (95% CI, 0.48-1.39); eGFR≤15 event rate, 9.1 for warfarin vs 13.5 for no warfarin; HR, 0.52 (95% CI, 0.16-1.65). Warfarin use in each CKD stratum was associated with lower hazards of the aggregate outcome (n = 9592 events) for event rates per 100 person-years: eGFR>60 event rate, 32.1 for warfarin vs 40.0 for no warfarin; HR, 0.76 (95% CI, 0.69-0.84); eGFR>30-60 event rate, 53.6 for warfarin vs 69.0 for no warfarin; HR, 0.75 (95% CI, 0.68-0.82); eGFR>15-30 event rate, 90.2 for warfarin vs 117.7 for no warfarin; HR, 0.82 (95% CI, 0.68-0.99); eGFR≤15 event rate, 86.2 for warfarin vs 138.2 for no warfarin; HR, 0.55 (95% CI, 0.37-0.83).

Conclusions and relevance: Warfarin treatment was associated with a lower 1-year risk for the composite outcome of death, MI, and ischemic stroke without a higher risk of bleeding in consecutive acute MI patients with atrial fibrillation. This association was not related to the severity of concurrent CKD.

Publication types

  • Multicenter Study
  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Anticoagulants / therapeutic use*
  • Atrial Fibrillation / complications*
  • Cardiovascular Diseases / complications
  • Female
  • Hemorrhage / chemically induced
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Myocardial Infarction / complications*
  • Patient Readmission
  • Prospective Studies
  • Registries
  • Renal Insufficiency, Chronic / complications*
  • Risk
  • Stroke / epidemiology
  • Stroke / prevention & control
  • Sweden / epidemiology
  • Thromboembolism / prevention & control
  • Warfarin / therapeutic use*


  • Anticoagulants
  • Warfarin