Clinical Prediction Model for Time in Therapeutic Range While on Warfarin in Newly Diagnosed Atrial Fibrillation.

BACKGROUND: Though warfarin has historically been the primary oral anticoagulant for stroke prevention in newly diagnosed atrial fibrillation (AF), several new direct oral anticoagulants may be preferred when anticoagulation control with warfarin is expected to be poor. This study developed a prediction model for time in therapeutic range (TTR) among newly diagnosed AF patients on newly initiated warfarin as a tool to assist decision making between warfarin and direct oral anticoagulants. METHODS AND RESULTS: This electronic medical record-based, retrospective study included newly diagnosed, nonvalvular AF patients with no recent warfarin exposure receiving primary care services through a large healthcare system in rural Pennsylvania. TTR was estimated as the percentage of time international normalized ratio measurements were between 2.0 and 3.0 during the first year following warfarin initiation. Candidate predictors of TTR were chosen from data elements collected during usual clinical care. A TTR prediction model was developed and temporally validated and its predictive performance was compared with the SAMe-TT2R2 score (sex, age, medical history, treatment, tobacco, race) using R2 and c-statistics. A total of 7877 newly diagnosed AF patients met study inclusion criteria. Median (interquartile range) TTR within the first year of starting warfarin was 51% (32, 67). Of 85 candidate predictors evaluated, 15 were included in the final validated model with an R2 of 15.4%. The proposed model showed better predictive performance than the SAMe-TT2R2 score (R2=3.0%). CONCLUSIONS: The proposed prediction model may assist decision making on the proper mode of oral anticoagulant among newly diagnosed AF patients. However, predicting TTR on warfarin remains challenging.

Temporal Trends in the Incidence, Prevalence, and Survival of Patients With Atrial Fibrillation From 2004 to 2016.

A growing epidemic of atrial fibrillation (AF) has been predicted, although no data on the AF burden has been reported for the United States since 2010. The objectives of this study were to (1) describe trends in AF incidence, prevalence, and postdiagnosis survival from 2004 to 2016 within a large health-care system and (2) extrapolate observed prevalence rates to the entire US population to estimate the national AF burden. This retrospective cohort study incorporates the patients and electronic medical record of the Geisinger Health System, an integrated health-care delivery system serving central and northeast Pennsylvania. Standardized incidence rates were calculated per 1,000 person-years by calendar year, and point prevalence rates estimated on July 1st of the respective years from 2004 to 2016. Rate ratios were estimated from Poisson regression as the annual relative change over time. A total of 464,363 patients met study inclusion criteria. Age- and sex-adjusted AF incidence rates increased over the study period: 4.7, 5.0, 5.8, and 6.2 in 2004, 2008, 2012, and 2016, respectively (rate ratio 1.03 per year, 95% confidence interval 1.02, 1.03). Age- and sex-adjusted prevalence rates increased consistently over time from 2.7%, 3.0%, 3.4%, to 4.1% in 2004, 2008, 2012, and 2016, respectively. In 2004, an estimated 6.1 million Americans had diagnosed AF, increasing to 6.7, 7.8, and 9.3 million in 2008, 2012, and 2016, respectively. Postdiagnosis survival has not improved in recent years. In conclusion, AF incidence and prevalence have increased steadily since 2004, whereas postdiagnosis survival has not improved.