Clinical Characteristics and Risk Factors of Immune Checkpoint Inhibitor‐Related Myocarditis: A Real World Observational Study

BACKGROUND: Rare occurrence, immune checkpoint inhibitors (ICI)-related myocarditis are poorly documented in the literature. RESEARCH DESIGN AND METHODS: We conducted a retrospective review of patients who had ICI until June 2023. Patient follow-up was extended until death or on May 2024. The primary outcome was the incidence of suspected ICI-related myocarditis. Logistic regression was used to investigate the associations between clinical characteristics and suspected ICI-related myocarditis. RESULTS: Among the included 8199 patients, 1638 (19.98%) patients developed suspected ICI-related myocarditis. Logistic regression revealed that thymomas and thymic carcinomas (OR 2.242; [95% CI, 1.132-4.440], p = 0.021), lung cancer (OR 1.259; [95% CI, 1.119-1.416], p < 0.001), older patients (OR 1.021; [95% CI, 1.016-1.026], p < 0.001), male (OR 1.213; [95% CI, 1.061-1.388], p = 0.005), block two or more immune checkpoints (OR = 1.391 [95% CI 1.058-1.828], p = 0.018), combined with hypertension (OR = 1.326 [95% CI 1.162-1.513], p < 0.001), or hyperlipidemia (OR = 1.656 [95% CI 1.302-2.107], p < 0.001) were associated with higher risk of suspected ICI-related myocarditis. CONCLUSIONS: This large, real-world cohort demonstrates that the incidence of suspected ICI-related myocarditis may be underestimated in previous literature. Routine cardiac surveillance is needed in high-risk patients receiving ICI therapy. TRIAL REGISTRATION: Registered at https://www.chictr.org.cn (identifier: ChiCTR2300075974).