Real-world cardiovascular toxicity of immune checkpoint inhibitors in an asian population: insights from a nationwide taiwanese registry

Background Immune checkpoint inhibitors (ICIs) have revolutionized oncologic treatment but are increasingly recognized to be associated with immune-related cardiovascular (CV) toxicities. While most epidemiological data were derived from Western populations, comprehensive real-world data from Asian cohorts remain limited. Therefore, in this nationwide Taiwanese registry, we aimed to characterize the burden and spectrum of ICI-associated CV complications. Methods We conducted a multicenter, retrospective registry enrolling adult cancer patients treated with ICIs across major medical centers in Taiwan. Baseline demographics, cancer characteristics, ICI regimens, and CV outcomes were systematically collected. Cardiovascular events were identified through structured electronic medical record review and included myocarditis, heart failure, arrhythmias, stroke, and other major cardiovascular events. Results As of November 30, 2025, a total of 1,200 patients were enrolled. The cohort was predominantly male (56.0%) and consisted largely of patients with advanced-stage malignancies (60%), with the majority aged between 51 and 70 years. Lung cancer represented the largest cancer subgroup, followed by hepatocellular carcinoma, colorectal cancer, breast cancer, and melanoma. PD-1 inhibitors were the most commonly prescribed ICIs (87.8%), while CTLA-4 and PD-L1 inhibitors were less frequently used. Cardiovascular events were documented in 105 patients (8.8%), including heart failure in 29 patients (2.4% of total cohort), arrhythmias in 14 (1.2%), stroke in 9 (0.8%), and myocarditis in 5 (0.4%). Notably, most CV events occurred in patients without previously documented cardiovascular disease, highlighting the need for proactive risk surveillance beyond traditional risk factors. Conclusions In this Taiwanese multicenter observational registry, approximately 1 in 12 patients receiving ICIs developed cardiovascular complications. These findings highlight a clinically meaningful burden of ICI-associated CV toxicity in real-world practice and highlight the need for proactive cardio-oncology risk assessment and continuous surveillance in patients undergoing immunotherapy.