Author + information
- Brent Williams,
- Michael Evans,
- Ashley Honushefsky and
- Peter Berger
Background: Though warfarin has historically been the primary oral anticoagulant (OAC) for stroke prevention in newly diagnosed atrial fibrillation (AF), several new direct OACs (DOACs) may be preferred when anticoagulation control with warfarin is expected to be poor. A decision aid may be helpful which assists practitioners in choosing between warfarin and DOACs. Accordingly, this study developed and validated a prediction model for time in therapeutic range (TTR) among newly diagnosed AF patients on newly-initiated warfarin, and compared this model with the SAMe-TT2R2 score.
Methods: An electronic medical record-based, retrospective cohort study of patients with new AF between 2003 and 2014 was conducted within a large integrated heath care system. Newly diagnosed, nonvalvular AF patients with no prior warfarin use subsequently prescribed warfarin within 90 days of diagnosis were included. Candidate predictors of TTR were chosen from data elements collected during usual clinical care, including demographics, vital signs, medical history including diagnoses and procedures, medications, and lab tests. TTR was considered primarily as a continuous variable, estimated as the percent of INR measurements between 2.0 and 3.0 inclusive over follow-up. A TTR prediction model was developed and temporally validated and its predictive performance compared with the SAMe-TT2R2 score via R2 and c-statistics.
Results: A total of 8867 newly diagnosed AF patients provided 439,926 INR measurements with a median (IQR) TTR of 55% (34, 68). Of 85 candidate predictors evaluated, 19 were included in the final validated model with R2 = 15.0%. The strongest predictors of low TTR included antiarrhythmic drug use, anemia, lung disease, aspirin use, and low red blood cell count. The proposed model showed better predictive performance than the SAMe-TT2R2 score in the validation cohort (R2 = 15.0% vs. 2.5%). The proposed model also showed better performance when splitting TTR at multiple cutpoints defining poor anticoagulation (c > 0.7 vs. c < 0.6).
Conclusions: The proposed prediction tool estimates the expected TTR on warfarin in newly diagnosed AF patients and may assist decision making on the proper mode of OAC.
Poster Hall, Hall C
Sunday, March 19, 2017, 9:45 a.m.-10:30 a.m.
Session Title: Arrhythmias and Clinical EP: Basic 5
Abstract Category: 4. Arrhythmias and Clinical EP: Basic
Presentation Number: 1281-111
- 2017 American College of Cardiology Foundation