(319) The risk of myocarditis, cardiomyopathy and cutaneous vasculitis associated with quetiapine in patients with schizophrenia and bipolar disorder.

Background: Quetiapine is a second-generation atypical antipsychotic used in the treatment of schizophrenia and bipolar affective disorder. The European Medicines Agency (EMA) recommended to include a warning about myocarditis, cardiomyopathy and cutaneous vasculitis in the product information of quetiapine in 2021. The association between quetiapine and each of the adverse events, myocarditis, cardiomyopathy, and cutaneous vasculitis, is not yet clear.

Objectives: This study aims to assess the risk of myocarditis, cardiomyopathy and cutaneous vasculitis associated with the use of quetiapine among patients diagnosed with schizophrenia and bipolar disorder in the Korean population.

Methods: We conducted a nested case-control study, using the National Health Insurance Database from 2002 to 2021. We selected patients aged 18 and older diagnosed with schizophrenia (ICD-10, F20-F29) or bipolar disorder (ICD-10, F31) between January 1, 2004, and December 31, 2021. For each case of cardiac diseases (myocarditis, cardiomyopathy) and cutaneous vasculitis, we used risk-set sampling and randomly matched 4 population controls by gender, age, and cohort entry date. The first date of cardiac diseases and cutaneous vasculitis diagnosis defined as the index date. We defined quetiapine use that it is investigated whether each subjects used quetiapine during 2 year, 6 month before index date in cardiac diseases group and cutaneous vasculitis group, respectively. Using conditional logistic regression, we calculated odds ratios (ORs) for cardiac diseases and cutaneous vasculitis associated with quetiapine use, adjusting for predefined potential confounders obtained from age, sex, history of disease and medication use. Subgroup analyses were conducted by sex, age groups and quetiapine average daily dose groups.

Results: The study population comprised 17,563 case patients with cardiac diseases and 8,881 case patients with cutaneous vasculitis who were matched with 70,252 and 35,524 population controls, respectively. The use of quetiapine was associated with an adjusted ORs 1.19 (95% confidence interval (CI): 1.14-1.24) for cardiac diseases and 1.17 (95% CI: 1.10-1.25) for cutaneous vasculitis. Particularly, the risk was higher in patients used quetiapine within current users 1.49 (95% CI: 1.42-1.57) in cardiac diseases group and 1.64 (95% CI: 1.48-1.81) in cutaneous vasculitis group.

Conclusions: We confirmed a significant relationship between the use of quetiapine and the risk of myocarditis, cardiomyopathy and cutaneous vasculitis. We suggest regular monitoring for myocarditis, cardiomyopathy and cutaneous vasculitis in clinical settings among individuals using quetiapine.