Cardiovascular Outcomes and Hospitalizations in Asian Patients Receiving Immune Checkpoint Inhibitors: A Population-based Study.

Immune checkpoint inhibitors (ICI) have known associations with cardiotoxicity. However, a representative quantification of the adverse cardiovascular events and cardiovascular attendances amongst Asian users of ICI has been lacking. This retrospective cohort study identified all ICI users in Hong Kong, China, between 2013 and 2021. All patients were followed up until the end of 2021 for the primary outcome of major adverse cardiovascular event (MACE; a composite of cardiovascular mortality, myocardial infarction, heart failure, and stroke). Patients with prior diagnosis of any component of MACE were excluded from all MACE analyses. In total, 4324 patients were analyzed (2905 (67.2%) males; median age 63.5 years old (interquartile range 55.4-70.7 years old); median follow-up 1.0 year (interquartile range 0.4-2.3 years)), of whom 153 were excluded from MACE analyses due to prior events. MACE occurred in 116 (2.8%) with an incidence rate (IR) of 1.7 [95% confidence interval: 1.4, 2.0] events per 100 patient-years; IR was higher within the first year of follow-up (2.9 [2.3, 3.5] events per 100 patient-years). Cardiovascular hospitalization(s) occurred in 188 (4.4%) with 254 episodes (0.5% of all episodes) and 1555 days of hospitalization (1.3% of all hospitalized days), for whom the IR of cardiovascular hospitalization was 5.6 [4.6, 6.9] episodes per 100 person-years with 52.9 [39.8, 70.3] days' stay per 100 person-years. Amongst Asian users of ICI, MACE was uncommon, and a small proportion of hospitalizations were cardiovascular in nature. Most MACE and cardiovascular hospitalizations occurred during the first year after initiating ICI.