Predictive values of age shock index and age modified shock index for in-hospital mortality in patients with ST-segment elevation myocardial infarction

Abstract

Abstract Background and Purpose This study aimed to evaluate the predictive values of admission age shock index (age SI) and age modified shock index (age MSI) for short-term outcomes in patients with ST-segment elevation myocardial infarction (STEMI). Methods 7324 patients with STEMI were included in the present study. Shock index (SI), modified shock index (MSI), age SI, age MSI and the TIMI score were calculated on admission. The primary outcome was all-cause mortality and the secondary outcomes were recurrent MI, cardiogenic shock and major adverse cardiovascular events (MACEs) during 30-day follow-up. Univariate and multivariate Cox regression were performed to evaluate the association between age SI, age MSI and outcomes. Predictive values of SI, MSI, age SI, age MSI and the TIMI score were evaluated and compared through analysis of the receiver operating characteristic (ROC) curves and integrated discrimination improvement (IDI). Results According to the ROC curve, the best cutoff of age SI for 30-day all-cause mortality were 50.0. Patients with elevated age SI had more comorbidities, received less evidence-based treatments and carried worse 30-day mortality. Multivariate Cox regressions demonstrated that age SI and age MSI were independent predictors of 30-day all-cause mortality and MACEs. The predictive values of age MSI for 30-day mortality were comparable to that of the TIMI score (c statistic: 0.743 vs. 0.758, z=1.740, p=0.082; IDI: 0.011, p=0.055) and better than that of SI (c statistic: 0.743 vs. 0.660, z=14.317, p<0.001; IDI: 0.046, p<0.001). The prognostic performance of age MSI was slightly inferior to that of the TIMI score (c statistic: 0.741 vs. 0.758, z=2.060, p=0.039; IDI: -0.001, p=0.846). Conclusion Age SI and age MSI were independent predictors for 30-day all-cause mortality and MACEs in patients with STEMI. The predictive value of age SI was comparable with the TIMI score but better than SI. Age SI and age MSI are practical risk stratification tools for STEMI.Figure.Receiver operating characterisTable.Discrimination and Calibration