start-ver=1.4 cd-journal=joma no-vol=49 cd-vols= no-issue=1 article-no= start-page=66 end-page=73 dt-received= dt-revised= dt-accepted= dt-pub-year=2026 dt-pub=20260110 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Exploratory Analysis for Development Predictive Models of Immune Checkpoint Inhibitor-Induced Myocarditis Using a Nationwide Claims Database en-subtitle= kn-subtitle= en-abstract= kn-abstract=Immune checkpoint inhibitors (ICIs), essential in cancer therapy, can cause severe immune-related adverse events (irAEs), including myocarditis with a high fatality rate. Currently, the pathogenesis, biomarkers, and risk factors of ICI-induced myocarditis (ICIM) are not fully understood. This exploratory study aimed to develop machine learning-based models to predict the onset of ICIM within 3 months of starting ICI therapy, using a large health insurance database. The models were constructed using the Light Gradient Boosting Machine (LightGBM) and Random Forest algorithms, incorporating clinical variables such as comorbidities and prior medication classifications. In this study, a strategy combining undersampling and bagging was used to minimize the impact of highly imbalanced datasets. The Random Forest model demonstrated superior performance compared with the LightGBM model, and the SHapley Additive exPlanations (SHAP) analysis for the Random Forest model revealed that the concurrent use of ICIs was the most important variable for predictions. Although predictive performance remains limited (AUROC ≈ 0.63), this exploratory framework demonstrates the feasibility of developing data-driven risk prediction models for ICIM. Future studies with expanded datasets and integration of laboratory parameters are warranted to improve predictive accuracy and potential clinical applicability. en-copyright= kn-copyright= en-aut-name=YamamotoReina en-aut-sei=Yamamoto en-aut-mei=Reina kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HamanoHirofumi en-aut-sei=Hamano en-aut-mei=Hirofumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=NakagomiKoki en-aut-sei=Nakagomi en-aut-mei=Koki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=UchiyamaMiyu en-aut-sei=Uchiyama en-aut-mei=Miyu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=MichiharaAyana en-aut-sei=Michihara en-aut-mei=Ayana kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=OzakiAya F. en-aut-sei=Ozaki en-aut-mei=Aya F. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=PatelPranav M. en-aut-sei=Patel en-aut-mei=Pranav M. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=TaniokaMaki en-aut-sei=Tanioka en-aut-mei=Maki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=ZamamiYoshito en-aut-sei=Zamami en-aut-mei=Yoshito kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=UeharaTakashi en-aut-sei=Uehara en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= affil-num=1 en-affil=Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University kn-affil= affil-num=2 en-affil=Department of Pharmacy, Okayama University Hospital kn-affil= affil-num=3 en-affil=Department of Clinical Pharmacy, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University kn-affil= affil-num=4 en-affil=Department of Clinical Pharmacy, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University kn-affil= affil-num=5 en-affil=Department of Pharmacy, Okayama University Hospital kn-affil= affil-num=6 en-affil=Department of Clinical Pharmacy Practice, School of Pharmacy & Pharmaceutical Sciences, University of California kn-affil= affil-num=7 en-affil=Division of Cardiology, School of Medicine, University of California kn-affil= affil-num=8 en-affil=Medical AI Project, Dentistry and Pharmaceutical Science, Okayama University Graduate School of Medicine kn-affil= affil-num=9 en-affil=Department of Pharmacy, Okayama University Hospital kn-affil= affil-num=10 en-affil=Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University kn-affil= en-keyword=machine learning kn-keyword=machine learning en-keyword=immune checkpoint inhibitor kn-keyword=immune checkpoint inhibitor en-keyword=myocarditis kn-keyword=myocarditis en-keyword=adverse event kn-keyword=adverse event END