A retrospective analysis of cardiovascular outcomes of clozapine treated individuals within Hunter New England.

BACKGROUND

Clozapine has demonstrated superiority in improving both positive and negative symptoms of treatment-resistant schizophrenia; however, there are associated treatment-limiting side effects, including myocarditis, cardiomyopathy and agranulocytosis.

AIM: This retrospective cohort study describes the prevalence of myocarditis, left ventricular (LV) dysfunction, cardiovascular risk factors and outcomes in a cohort of patients maintained on clozapine therapy.

METHODS

Data were retrospectively collated from patients who had a diagnosis of schizophrenia, had been managed with clozapine at any stage during their care and undergone at least one echocardiogram.

RESULTS

Between March 2020 and September 2021 674 patients were identified, 71% were male, with a mean age of 47 years old (interquartile range (IQR) 40-57). The mean duration of clozapine use was 7 years (IQR 4-13). The overall mortality was 5.54% during the follow-up period. Myocarditis was identified in one patient (0.15%) within the first 30 days, and an additional five cases were identified over the follow-up period (0.89%). The combined incidence of heart failure (HF) and myocarditis was 1.6% during the follow-up period. There was no association between LV size and function at baseline or during follow-up and adverse cardiac outcomes (comprising death, myocarditis, HF). Older age at initiation of therapy and baseline E/e' ratio were associated with risk of HF and myocarditis.

CONCLUSION

The overall incidence of myocarditis and HF during follow-up was low, with surveillance echocardiography offering limited predictive value. Patients maintained on clozapine are at risk of significant cardiovascular sequelae, likely reflecting an adverse risk factor profile.