Incidence of atrial fibrillation/flutter, one-year re-admission rates, and practice patterns among patients <65 years of age: a Danish nationwide study

Abstract Background/Introduction The general atrial fibrillation/flutter (AF) population is well explored and described, but there is sparse data on temporal changes in the incidence, AF-readmission rates, and practice patterns in patients with AF under 65 years of age from unselected cohorts. Purpose To investigate temporal changes, AF readmission rates, and practice patterns in patients under 65 years of age with first-time AF diagnosed between 2000–2018. Methods Using Danish nationwide registries, we identified patients >18 years and <65 years with a first-time AF-diagnosis from 2000–2018. The cohort was categorized according to calendar periods; 2000–2002, 2003–2006, 2007–2010, 2011–2014 and 2015–2018. Incidence rate (IR) of AF per 100,000 person years (PY), AF-readmission, and practice patterns of medical treatment, electrical cardioversion, and catheter ablation was investigated in the first year following AF-diagnosis. Results In this study 60,917 patients were included; 8,150 patients (13.4%) in 2000–2002, 11,898 (19.5%) in 2003–2006, 13,560 (22.3%) in 2007–2010, 14,167 (23.3%) in 2011–2014 and 13,142 (21.6%) in 2015–2018. No major differences were seen in patient characteristics according to calendar period. A stepwise increase, as seen in the Table, in the crude IR of AF per 100,000 PY was observed across calendar periods, except for 2015–2018 (Crude IR [95% CI]: 2000–2002: 78.7 [77.0; 80.4], 2003–2006: 86.3 [84.7; 87.8], 2007–2010: 97.9 [96.3; 99.6], 2011–2014: 102.3 [100.7; 104.0], 2015–2018: 93.6 [92.0; 95.2], while no difference in AF readmission was identified (AF-readmissions: 2000–2002: 32.7%, 2003–2006: 31.1%, 2007–2010: 32.2%, 2011–2014: 32.1% and 2015–2018: 31.7%), as seen in the Figure, right panel. In the first year following AF-diagnosis, the cumulative incidence of catheter ablation increased stepwise from 1.2% in 2000–2002 to 7.6% in 2015–2018 and electrical cardioversion from 2.0% in 2000–2002 to 8.7% in 2015–2018 (Figure, left panel). Treatment with oral anticoagulant therapy (OAC) increased from 28.5% in 2000–2002 to 47.8% in 2015–2018, while there was no change in treatment with rhythm or rate medication therapy. Conclusion From 2000–2018, we found an increase in the incidence of atrial fibrillation/flutter (AF) in patients <65 years from 78.7/100,000 person years (PY) to 93.6/100,000 PY and an increase in the use of catheter ablation, electrical cardioversion and OAC in the first year following first-time AF-diagnosis. AF readmission rates were stable over calendar periods. Funding Acknowledgement Type of funding sources: None.