Cardiac arrhythmias in cancer patients using the nationwide claim‐based database in Japan

Background: Cardio-oncology has recently developed as a new discipline. No study using a Nationwide Claim-Based Database has examined the association between cancer and arrhythmia in Japan. Methods: JROAD-DPC (Japanese Registry Of All cardiac and vascular Diseases - Diagnosis Procedure Combination) is a nationwide claims database using data from the Japanese Diagnosis Procedure Combination/Per Diem Payment System. Among 11 297 525 records found between April 2012 and March 2021 from 1119 hospitals, 2 976 362 patients with arrhythmias were studied and divided into categories using cancer. Results: The prevalence rate of cancers was 7.51% of the patients hospitalized for arrhythmias, and the prevalence of cancer increased with time. The prevalence rate of Atrial fibrillation (AF) and/or atrial flutter (AFL) was 70.6% and 60.7% of arrhythmic patients with and without cancer, respectively. Pneumonia (7.41%) was the first major infectious complication in arrhythmic patients with cancers. Arrhythmic patients with cancers had significantly higher Barthel index (65.2 at admission and 72.5 at discharge) and prevalences of hyperuricemia (HU) and chronic kidney disease (CKD) (6.13% and 9.67%) than those without cancer. The rate of emergency hospitalization was higher in arrhythmic patients with cancers than those without cancer (58.9% vs. 57.6%). Conclusion: Cancers were frequently observed in arrhythmic patients, and the prevalences increased with time. AF and/or AFL were the most common arrhythmias of cancer patients. Arrhythmic patients with cancers had significantly higher Barthel index and prevalences of HU and CKD than those without cancer.