The Relationship between Holter Electrocardiography and Atrial Fibrillation Diagnosis Using Real-World Data in Japan

The relationship between Holter electrocardiography (ECG) and atrial fibrillation (AF) diagnosis in the real world has not been widely evaluated in Japan.This is a claims-based retrospective study using a health insurance claims database provided by DeSC Healthcare Corporation. We identified patients with at least one Holter for any purpose during the data period from April 2015 to November 2020 and without diagnosis of AF before the tests (n = 19,739). We obtained a whole picture of Holter and AF diagnosis after correcting for population distribution bias in the dataset. Based on this picture and the assumption that the patient had AF at the 1^st Holter whose AF was detected for the first time at the second or subsequent Holter, we estimated the number of diagnosis with AF and overlooked AF by initial Holter. We conducted sensitivity analyses changing the definition of AF, the potential detection period, and the washout period (a period required to avoid including patients who have already been diagnosed with AF or who have already undergone several Holters) to confirm the validity of the base scenario.Among patients for analysis, 88.4% had only one Holter. The percentage of AF diagnosis by initial Holter was 7.6%. The percentage of AF overlooked by initial Holter was estimated to be 31.4% and this value did not change much by sensitivity analyses.It was estimated that approximately 30% of AF patients were overlooked by initial Holter, and reducing the overlooked rate will be a clinical challenge.