Risk factors of in-hospital death in patients with acute ST elevation myocardial infarction

Totally 9668 patients with acute STEMI in Beijing Anzhen Hospital, Capital Medical University from January 2002 to August 2019. Inclusion criteria: (1) patient hospitalized with STEMI; (2) age of more than 18 years. We established the diagnosis of acute myocardial infarction (AMI) and STEMI base on fourth universal definition of myocardial infarction [2]. Exclusion criteria: none. Evaluation and diagnosis of in‐hospital death


Background
Coronary heart disease remains the leading cause of mortality [1]. Prevention of in-hospital death is a crucial step in improving prognosis of patients with ST elevation myocardial infarction (STEMI). We want to investigate the risk factors of in-hospital death.

Source of data
Totally 9668 patients with acute STEMI in Beijing Anzhen Hospital, Capital Medical University from January 2002 to August 2019.
We established the diagnosis of acute myocardial infarction (AMI) and STEMI base on fourth universal definition of myocardial infarction [2].

Evaluation and diagnosis of in-hospital death
All causes for in-hospital death is defined as cardiac or noncardiac death during hospitalization.

Predictors
We selected 11 predictor variables for inclusion in our prediction rule. They were shown in Table 1. PCI = percutaneous coronary intervention, CABG = coronary artery bypass grafting. Atrial fibrillation is defined as all type of atrial fibrillation during hospitalization. Atrioventricular block is defined as all type of atrioventricular block during hospitalization.

Statistical analysis
We followed the methods of Li et al. 2019 [3].

Participants and predictors of in-hospital death
Totally 188 patients had in-hospital death (in-hospital death group) and 9480 patients had no in-hospital death (control group). The results are shown in Table 1.  Tables 2 and 3.

3
We drew the receiver operating characteristic curve. The area under the receiver operating characteristic curve was 0.94 ± 0.007, 95% CI = 0.926-0.954.

Study limitations
This is a single-center experience. Some patients were enrolled > 10 years ago, thus their treatment may not conform to current standards and techniques.

Discussion
We investigated the predisposing factors of in-hospital death. A frequency of in-hospital death was 1.9% (188/9668). Killip classification is an independent risk factor of in-hospital death. In our study, patients with Killip class IV were at 64.7 higher risk of in-hospital death than patients with Killip class I-III. Not underwent PCI is an independent risk factor of in-hospital death. Patients who do not get successful reperfusion are at higher risk of early complications and death [4]. Age is an independent risk factor of in-hospital death. Older patients have more comorbidities and are less likely to receive reperfusion therapy [5,6]. Elderly patients are also at particular risk of bleeding [4].

Conclusions
Age, not underwent PCI during hospitalization, and Killip classification are independent risk factors for predicting inhospital death in patients with acute STEMI.
Author contributions Yong Li contributed to generating the study data, analysed, interpreted the study data, drafted the manuscript, and revised the manuscript. Yong Li is responsible for the overall content as guarantor. All authors have read and approved the manuscript.
Funding None.

Conflicts of interests
The authors declare that they have no competing interests.
Ethics approval and consent to participate Ethic committee approved the study. Approved No. of ethic committee: 2019039X. Name of the ethic committee: Ethics committee of Beijing Anzhen Hospital Capital Medical University. It was a retrospective analysis and informed consent was waived by Ethics Committee of Beijing Anzhen Hospital Capital Medical University.

Statement of human and animal rights
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The study was not conducted with animals.
Informed consent It was a retrospective analysis and informed consent was waived by Ethics Committee of Beijing Anzhen Hospital Capital Medical University.

Availability of data and material
The data used to support the findings of this study are included within the supplementary material.
Code availability (software application or custom code) The data are demographic, clinical, and angiographic characteristics of patients with acute STEMI. DIE = in-hospital death; AGE = age; G = gender; HBP = history of hypertension; DM = history of diabetes; OMI = history of myocardial infarction; HPCI = history of percutaneous coronary intervention; CABG = history of coronary artery bypass grafting; HCD = history of cerebrovascular disease; CKD = history of chronic kidney disease; KI = Killip I; KII = Killip II; KIII = Killip III; KIV = Killip IV; AVB = atrioventricular block; ALLAF = atrial fibrillation; PCI = underwent PCI during hospitalization.
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creat iveco mmons .org/licen ses/by/4.0/.