Nishant Nerella, MD
How well does a risk stratification scheme (Anticoagulation and Risk Factors in Atrial Fibrillation [ATRIA] score) predict risk for warfarin-associated hemorrhage in patients with atrial fibrillation (AF)? How does it compare with other risk prediction schemes?
Cohort study with 32 888 person-years of warfarin exposure.
Kaiser Permanente of Northern California integrated healthcare system in the USA.
9186 patients (derivation cohort n = 6123; validation cohort n = 3063) who had nonvalvular, nontransient AF. 30% of patients contributed data for > 1 period of warfarin use, and 8% contributed data for > 2 periods of warfarin use.
5-item ATRIA score (score range 0 to 10): anemia and severe renal disease (3 points each), age ≥ 75 years (2 points), and hypertension and past hemorrhage (1 point each). ATRIA risk categories: low risk for hemorrhage, score ≤ 3; intermediate risk, score = 4; and high risk, score ≥ 5.
Major extracranial (gastrointestinal, genitourinary, or retroperitoneal) and intracranial (intracerebral, subarachnoid, or subdural) hemorrhages that occurred during warfarin use or ≤ 5 days after cessation of warfarin use.
After 32 888 person-years of warfarin exposure, incidence of major hemorrhage was 1.4% per year. In the validation cohort, c-index for discrimination of risk using the ATRIA score was 0.74 (95% CI 0.70 to 0.78); calibration was assessed using the goodness-of-fit test (P = 0.29). Incidence of major hemorrhage increased with ATRIA risk category (Table). ATRIA score had similar or better discrimination than 6 other risk stratification schemes (Table).
In patients with atrial fibrillation, a 5-item risk stratification score predicted risk for warfarin-associated major hemorrhage.
*ATRIA = Anticoagulation and Risk Factors in Atrial Fibrillation; HEMORR2HAGES = Hepatic/renal disease, Ethanol abuse, Malignancy, Older age, Reduced platelet count, Rebleeding risk, Hypertension, Anemia, Genetic factors, Excessive fall risk, and Stroke; RIETE = Registro Informatizado de la Enfermedad Tromboembólica.
Nerella N. A 5-item score predicted risk for warfarin-associated major hemorrhage in patients with atrial fibrillation. Ann Intern Med. ;155:JC5–13. doi: 10.7326/0003-4819-155-10-201111150-02013
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Published: Ann Intern Med. 2011;155(10):JC5-13.
Cardiology, Rhythm Disorders and Devices.
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