Plateauing atrial fibrillation burden in acute ischemic stroke admissions in the United States from 2010 to 2020

Background: Utilization of oral anticoagulants for acute ischemic stroke (AIS) prevention in patients with atrial fibrillation (AF) increased in the United States over the last decade. Whether this increase has been accompanied by any change in AF prevalence in AIS at the population level remains unknown. The aim of this study is to evaluate trends in AF prevalence in AIS hospitalizations in various age, sex, and racial subgroups over the last decade. Methods: We used data contained in the 2010-2020 National Inpatient Sample to conduct a serial cross-sectional study. Primary AIS hospitalizations with and without comorbid AF were identified using International Classification of Diseases Codes. Joinpoint regression was used to compute annualized percentage change (APC) in prevalence and to identify points of change in prevalence over time. Results: Of 5,190,148 weighted primary AIS hospitalizations over the study period, 25.1% had comorbid AF. The age- and sex-standardized prevalence of AF in AIS hospitalizations increased across the entire study period 2010-2020 (average APC: 1.3%, 95% confidence interval (CI): 0.8-1.7%). Joinpoint regression showed that prevalence increased in the period 2010-2015 (APC: 2.8%, 95% CI: 1.9-3.9%) but remained stable in the period 2015-2020 (APC: -0.3%, 95% CI: -1.0 to 1.9%). Upon stratification by age and sex, prevalence increased in all age/sex groups from 2010 to 2015 and continued to increase throughout the entire study period in hospitalizations in men 18-39 years (APC: 4.0%, 95% CI: 0.2-7.9%), men 40-59 years (APC: 3.4%, 95% CI: 1.9-4.9%) and women 40-59 years (APC: 4.4%, 95% CI: 2.0-6.8%). In contrast, prevalence declined in hospitalizations in women 60-79 (APC: -1.0%, 95% CI: -0.5 to -1.5%) and women > 80 years over the period 2015-2020 but plateaued in hospitalizations in similar-aged men over the same period. Conclusion: AF prevalence in AIS hospitalizations in the United States increased over the period 2010-2015, then plateaued over the period 2015-2020 due to declining prevalence in hospitalizations in women > 60 years and plateauing prevalence in hospitalizations in men >= 60 years.