Decision analysis and guidelines for anticoagulant therapy to prevent stroke in patients with atrial fibrillation

Background Clinical guidelines are needed on whether or not to use anticoag ulant therapy to prevent stroke in patients with non-valvular atrial fibril lation. We did a Markov decision analysis to model decision-making with reg ard to warfarin treatment in patients with atrial fibrillation, and used th e model to develop evaluative guidelines. Methods The decision analysis involved a systematic literature review suppl emented by patients' estimates of the quality of life associated with diffe rent states of health, secondary analysis of stroke-registry data, and esti mation of service costs; it also incorporated a sensitivity analysis. The d erived guidelines were subsequently applied to a cohort of patients with at rial fibrillation, Findings We constructed decision tables for 12 age and sex groups. For most risk combinations, warfarin treatment would have decreased healthcare cost s and increased quality-of-life years, although the clinical decision was s ensitive to patients' preferences and to the estimate of warfarin's effecti veness. 97% of women with atrial fibrillation older than 75 years, and 69% aged 65-74 would have been recommended for treatment; for men, the correspo nding figures would have been 75% and 53%, With the upper quartile for the loss of quality of life associated with being on warfarin treatment (1.00), all but two of the 116 patients without contraindications would have been treated, whereas with the lower quartile (0.92), only 27 of 116 would have been treated. Interpretation Decision analysis is useful in the incorporation of complex probabilistic data into informed decision-making, the identification of fac tors influencing such decisions, and the subsequent development of evaluati ve guidelines.