A risk model predicted major bleeding in older patients with atrial fibrillation receiving warfarin therapy.

M e t h o d s Design: 2 cohort studies, 1 for derivation and 1 for validation from the National Registry of Atrial Fibrillation. Setting: United States. Patients: 26 345 patients ≥ 65 years of age (88% > 70 y, 43% > 80 y, 53% women; 19 875 for derivation, 6470 for validation) with AF who were receiving warfarin therapy at hospital discharge. Exclusion criteria included discharge against medical advice, transfer to another acute care hospital, enrollment in managed care, or death during hospitalization. Description of prediction guide: The risk score (range 0 to 4.17) categorized patients into low(score ≤ 1.07), moderate(score > 1.07 to < 2.19), or high-risk (score ≥ 2.19) groups. The risk score was a summation of the log likelihood of 8 clinical variables: age (≥ 70 y = 0.49), sex (women = 0.32), remote bleeding = 0.58, recent bleeding = 0.62, alcohol or drug abuse = 0.71, diabetes = 0.27, anemia = 0.86, and antiplatelet drugs = 0.32. Outcomes: Hospitalization for major acute bleeding within 90 days of index hospital discharge. M a i n r e s u l t s 8 independent clinical predictors of major bleeding were identified in the derivation cohort (Table). In the validation cohort, major bleeding events developed in 35 (0.9%) low-risk patients {likelihood ratio [LR] 0.6}*, 48 (2.0%) moderate-risk patients {LR 1.4}*, and 12 (5.4%) high-risk patients {LR 3.8}* (P < 0.001). The area under the receiver-operating characteristic (AUROC) curve was 0.632. This model had similar predictive characteristics compared with 2 previous BRMs: Outpatient Bleeding Risk Index (AUROC curve 0.613) and Kuijer and colleagues’ model (AUROC curve 0.503).