A Novel Risk Score to Predict In-Hospital Mortality in Patients With Acute Myocardial Infarction: Results From a Prospective Observational Cohort

Abstract

Objectives: The aim of this study was to develop and validate a novel risk score to predict in-hospital mortality in patients with acute myocardial infarction (AMI) using the Heart Failure after Acute Myocardial Infarction with Optimal Treatment (HAMIOT) cohort in China.

Methods: The HAMIOT cohort was a multicenter, prospective, observational cohort of consecutive patients with AMI in China. All participants were enrolled between December 2017 and December 2019. The cohort was randomly assigned (at a proportion of 7:3) to the training and validation cohorts. Logistic regression model was used to develop and validate a predictive model of in-hospital mortality. The performance of discrimination and calibration was evaluated using the Harrell's c-statistic and the Hosmer-Lemeshow goodness-of-fit test, respectively. The new simplified risk score was validated in an external cohort that included independent patients with AMI between October 2019 and March 2021.

Results: A total of 12,179 patients with AMI participated in the HAMIOT cohort, and 136 patients were excluded. In-hospital mortality was 166 (1.38%). Ten predictors were found to be independently associated with in-hospital mortality: age, sex, history of percutaneous coronary intervention (PCI), history of stroke, presentation with ST-segment elevation, heart rate, systolic blood pressure, initial serum creatinine level, initial N-terminal pro-B-type natriuretic peptide level, and PCI treatment. The c-statistic of the novel simplified HAMIOT risk score was 0.88, with good calibration (Hosmer-Lemeshow test: P = 0.35). Compared with the Global Registry of Acute Coronary Events risk score, the HAMIOT score had better discrimination ability in the training (0.88 vs. 0.81) and validation (0.82 vs. 0.72) cohorts. The total simplified HAMIOT risk score ranged from 0 to 121. The observed mortality in the HAMIOT cohort increased across different risk groups, with 0.35% in the low risk group (score ≤ 50), 3.09% in the intermediate risk group (50 < score ≤ 74), and 14.29% in the high risk group (score > 74).

Conclusion: The novel HAMIOT risk score could predict in-hospital mortality and be a valid tool for prospective risk stratification of patients with AMI.

Clinical trial registration: [https://ichgcp.net/clinical-trials-registry/NCT03297164" title="See in ClinicalTrials.gov">NCT03297164].

Keywords: acute myocardial infarction; in-hospital mortality; integrated discrimination index; logistic regression model; net reclassification improvement; risk score.

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Copyright © 2022 Li, Zhang, Wang, Yu, Jia, Hou, Li, Zhang, Yang, Liu, Lu, Tan, Yu and Li.

Figures

FIGURE 1

Study flow chart of the HAMIOT Cohort Study. From December 2017 to December 2019, 12,043 patients with AMI were randomly assigned into the training (n = 8,431) and validation (n = 3,612) cohorts. HAMIOT, the Heart failure after Acute Myocardial Infarction with Optimal Treatment; AMI, acute myocardial infarction.

FIGURE 2

Odds ratio of in-hospital mortality in multivariate logistic regression model. OR, odds ratio; CI, confidence interval; STEMI, ST-segment elevation myocardial infarction; NSTEMI, non-ST-segment elevation myocardial infarction; SBP, systolic blood pressure; NT-proBNP, N-terminal pro-B-type natriuretic peptide; PCI, percutaneous coronary intervention.

FIGURE 3

(A) Risk score calculator of in-hospital mortality for patients with AMI. (B) Distribution of HAMIOT risk score and the probability of in-hospital mortality. (C) Relationship between the observed and expected in-hospital mortality across deciles of risk. (D) Observed in-hospital mortality of HAMIOT cohort and external cohort stratified by three risk groups (low risk, intermediate risk, and high risk groups). The observed in-hospital mortality rates were 0.35, 3.09, and 14.29% in the HAMIOT cohort, and 0.31, 2.21, and 11.39% in the external cohort, respectively. HAMIOT, the Heart failure after Acute Myocardial Infarction with Optimal Treatment, STEMI, ST-segment elevation myocardial infarction; NSTEMI, non-ST-segment elevation myocardial infarction; SBP, systolic blood pressure; NT-proBNP, N-terminal pro-B-type natriuretic peptide; PCI, percutaneous coronary intervention.

FIGURE 4

The ROC Curves of the HAMIOT and the GRACE risk score. (A) In the training cohort, the c-statistic in the HAMIOT score 0.88(0.84,0.91) was higher than the GRACE score 0.81(0.77,0.84). (B) In the validation cohort, the c-statistic in the HAMIOT score 0.82(0.76,0.88) was higher than the GRACE 0.72(0.65,0.8). HAMIOT, the Heart failure after Acute Myocardial Infarction with Optimal Treatment; GRACE, the Global Registry of Acute Coronary Events; ROC, receiver operating characteristic.