Usability of an atrial fibrillation anticoagulation decision-support tool.

Introduction: In individuals with nonvalvular atrial fibrillation, anticoagulant therapy with warfarin reduces the rate of thromboembolic events but increases the risk of bleeding. Treatment decisions frequently are inconsistent with guidelines. A new web-based atrial fibrillation decision-support tool (AF-DST) provides patient-specific information on the risk-benefit tradeoff of anticoagulation.

Methods: The authors performed a pilot usability testing study of the AF-DST with 4 medical house officers and 4 attending physicians by simulating 9 outpatient clinical encounters involving tradeoffs between risks and benefits of anticoagulation. They recorded positive and negative critical incidents in the simulations and assessed satisfaction with use of the AF-DST by the Computer System Usability Questionnaire (CSUQ; score range on each item: 1 = strongly disagree to 7 = strongly agree).

Results: Users found the AF-DST to be helpful and had high CSUQ scores (mean item score, 6.3). Usability testing identified 6 positive and 14 negative critical incidents. Participants felt that the AF-DST guided them toward the correct decision. Nevertheless, they desired more information on the "black box" calculations and ignored alerts. Training level appeared to affect how the AF-DST was used, in particular, how users interacted with the AF-DST.

Conclusions: Overall satisfaction with the AF-DST was high and the tool effectively communicated recommendations and uncertainty. Usability testing identified design issues and potential errors caused by decision-support tool use; these gaps should be addressed prior to clinical implementation.