Mortality and Revascularization among Myocardial Infarction Patients with Schizophrenia: A Population-Based Cohort Study

Abstract

Background:Cardiovascular disease is a major source of mortality in schizophrenia, and access to care after acute myocardial infarction (AMI) is poor for these patients.Aims:To understand the relationship between schizophrenia and access to coronary revascularization and the impact of revascularization on mortality among individuals with schizophrenia and AMI.Method:This study used a retrospective cohort of AMI in Ontario between 2008 and 2015. The exposure was a diagnosis of schizophrenia, and patients were followed 1 year after AMI discharge. The primary outcome was all-cause mortality within 1 year. Secondary outcomes were cardiac catheterization and revascularization (percutaneous coronary intervention or coronary artery bypass graft). Cox proportional hazard regression models were used to study the relationship between schizophrenia and mortality, and the time-varying effect of revascularization.Results:A total of 108,610 cases of incident AMI were identified, among whom 1,145 (1.1%) had schizophrenia. Schizophrenia patients had increased mortality, with a hazard ratio (HR) of 1.55 (95% CI, 1.37 to 1.77) when adjusted for age, sex, income, rurality, geographic region, and comorbidity. After adjusting for time-varying revascularization, the HR reduced to 1.38 (95% CI, 1.20 to 1.58). The impact of revascularization on mortality was similar among those with and without schizophrenia (HR: 0.42; 95% CI, 0.41 to 0.44 vs. HR: 0.40; 95% CI, 0.26 to 0.61).Conclusions:In this sample of AMI, mortality in schizophrenia is increased, and treatment with revascularization reduces the HR of schizophrenia. The higher mortality rate yet similar survival benefit of revascularization among individuals with schizophrenia relative to those without suggests that increasing access to revascularization may reduce the elevated mortality observed in individuals with schizophrenia.