Systematic review and meta-analysis of increased ischemic heart disease vulnerability in schizophrenia patients

Abstract

Abstract Background Ischemic heart disease (IHD) is the leading cause of death in Europe and worldwide and past studies have shown its unusually high prevalence in schizophrenia patients. We conducted the first review to synthesise the prevalence of ischemic heart disease (IHD) in schizophrenia patients of the developed world in a quantitative review using the PRISMA standards (Preferred Reporting Items for Systematic Reviews and Meta-Analysis). Purpose The aim of this systematic review and meta-analysis is to assess the current state of research on the prevalence of ischemic heart disease in schizophrenia patients in the developed world. Methods Studies included were primary research in the form of population-based cohort studies for both males and females. Articles that were not in English, not peer-reviewed, were unspecific in cardiac conditions and mental illnesses, or of an unsuitable data type were excluded. The searches were conducted in PubMed and Embase (Ovid) on 12th of October 2022, and last updated on January 4th, 2023. Data were extracted and analysed in R for meta-analysis, with possible biases investigated. The protocol and review were carried out in accordance with the PRISMA guidelines and are accessible online at Open Science Framework. Results Five population-based longitudinal cohort studies were included from various regions of the developed world, four of which were meta-analysed. In all studies, schizophrenia patients had a higher risk of IHD than controls, which was supported by the meta-analysis indicating that schizophrenics are 1.66 times more likely to develop IHD (HR = 1.66; 95%CI: 1.30-2.12; p<0.01). However, the analyses displayed significant heterogeneity (I2 = 82%). Furthermore, all studies demonstrated a particularly concerning vulnerability for IHD among female and younger schizophrenia patients. Conclusions This review demonstrated a significant increase in the risk of IHD among schizophrenia patients, particularly in younger age groups and females. Although the small number of studies with diverse patient characteristics (inpatient or both inpatient and outpatient) in each study limited the precision of the overall hazard ratio, the meta-analysis confirmed the negative trend presented in the review process. The especially broad coverage of the sample population in the publications has suggested that this risk has persisted throughout the socio-economic and medical advancements in the developed world since the Second World War.