Scraping up CHA2DS2-VASc - defining components of the acronym in a nationwide registry study
Authors: Kouki E , Halminen O , Haukka J , Linna M , Mustonen P , Putaala J , Itainen-Stromberg S , Kinnunen J , Aro A , Niiranen J , Penttila T , Tiili P , Hartikainen J , Airaksinen JEK , Lehto M 
Published: May 2021

Abstract

Funding Acknowledgements
Type of funding sources: Public hospital(s). Main funding source(s): Helsinki and Uusimaa Hospital district Finnish foundation for cardiovascular research

Introduction
Atrial fibrillation (AF) is a major cause of ischemic stroke. The risk of stroke is strongly associated with age, sex and comorbidities of the patients. Therefore, it is crucial that the comorbidities are consistently recorded in medical records as well as health care registries.

Purpose
This study aims to evaluate the prevalence of the comorbidities related to AF stroke risk in Finnish nationwide population registries, and assess how the use and combination of these registries affect the calculated CHA2DS2-VASc risk score. The comorbidities evaluated were Hypertension, Diabetes, Stroke or TIA, Heart Failure, and Vascular Disease.

Methods
The Finnish AntiCoagulation in Atrial Fibrillation (FinACAF) study collected data on all Finnish AF patients from 1st January 2004 to 31st December 2018. Due to the initiation of the national primary care register in 2012, this substudy uses the data of patients with a new AF diagnosis during 2012-2018 (n = 168 353). Using a unique personal identification code, individual patient data were linked from the Finnish national health care registries "AvoHILMO" (primary care) and "HILMO" (secondary and tertiary care), National Prescription Register (ATC codes of purchased medication) and the National Reimbursement Register for reimbursed medication upheld by the Social Insurance Institute (KELA).
Results
The average CHA2DS2-VASc risk score when entering the cohort, and including information from all registries, equaled 2.91 for men (mean age 70.0 years) and 4.42 for women (mean age 76.9 years). The highest prevalence of diabetes and hypertension were found based on the National Reimbursement Register (ATC codes). Stroke or TIA and heart failure were identified almost exclusively based on secondary and tertiary hospital records.
The table represents our results.

Conclusion
Comprehensive registry analysis of AF patients requires the inclusion of both hospital and medication data. The role of primary care information was limited. Comorbidity and CHA2DS2-VASc weight Total Prevalence Primary care ICD-10 codes Primary care ICPC-2 codes Secondary and tertiary care ICD-10 codes ATCcodes Medication reimbursement codes Hypertension 1 82%137 317 28%47 337 13%21 427 39%66 252 77%130 400 7%10 957 Diabetes 1 24%41 017 13%22 666 13%22 547 14%23 793 21%35 942 12%20 295 Stroke or TIA 2 17%28 653 4%6 254 1%1 968 16%27 379 - - Heart Failure 1 18%29 827 5%7 630 1%1 398 16%26 366 - 1%1 908 Vascular Disease1 28%47 420 12%19 581 2%3 265 25%41 647 - 7%11 802 Average CHA2DS2-VASc contribution 1.86 0.65 0.31 1.26 0.99 0.26 The prevalence of the comorbidities and average CHA2DS2-VASc risk score contribution by registry and combined.