Cardiovascular events after the initiation of immune checkpoint inhibitors.

We sought to clarify the incidence of major adverse cardiac events (MACE) after the initiation of immune checkpoint inhibitors (ICIs). We analyzed the JMDC Claims Database between 2005 and 2021. The study included 2972 patients with no history of cardiovascular disease and a prescription for an ICI. The primary outcome was the incidence of MACE, including myocarditis, pericarditis, Takotsubo cardiomyopathy, atrio-ventricular block, heart failure, myocardial infarction, and stroke. The median age of study participants was 59 (Q1-Q3 53-65) years, and 2163 participants (72.8%) were male. Lung cancer was the most common cancer site (n = 1603). Among ICIs, programmed cell death-1 (PD-1) was most frequently used, and a combination ICI treatment was conducted in 110 patients (3.7%). During a mean follow-up of 358 ± 327 days, 419 MACE events were recorded. The incidence rate of myocarditis, pericarditis, Takotsubo cardiomyopathy, atrio-ventricular block, heart failure, myocardial infarction, and stroke was 3.4, 142.3, 10.3, 17.2, 1191.2, 55.2, and 278.5 per 10,000 person-years, respectively. The incidence of cardiovascular events was higher within 180 days after the initial prescription of ICI. The continuation rate of ICI after MACE was 38.4%. In conclusion, our analysis of a nationwide epidemiological dataset demonstrated the incidence of MACE after the initiation of ICI treatment. The incidence of heart failure was higher than expected, and the continuation rate of ICI treatment after MACE was low. Our results indicated the importance of monitoring and prevention of cardiovascular events in cancer patients requiring ICI treatment.