Validation of the Shock Index, Modified Shock Index, and Age Shock Index for Predicting Mortality of Geriatric Trauma Patients in Emergency Departments

Abstract

The shock index (SI), modified shock index (MSI), and age multiplied by SI (Age SI) are used to assess the severity and predict the mortality of trauma patients, but their validity for geriatric patients is controversial. The purpose of this investigation was to assess predictive value of the SI, MSI, and Age SI for geriatric trauma patients. We used the Emergency Department-based Injury In-depth Surveillance (EDIIS), which has data from 20 EDs across Korea. Patients older than 65 years who had traumatic injuries from January 2008 to December 2013 were enrolled. We compared in-hospital and ED mortality of groups categorized as stable and unstable according to indexes. We also assessed their predictive power of each index by calculating the area under the each receiver operating characteristic (AUROC) curve. A total of 45,880 cases were included. The percentage of cases classified as unstable was greater among non-survivors than survivors for the SI (36.6% vs. 1.8%, P < 0.001), the MSI (38.6% vs. 2.2%, P < 0.001), and the Age SI (69.4% vs. 21.3%, P < 0.001). Non-survivors had higher median values than survivors on the SI (0.84 vs. 0.57, P < 0.001), MSI (0.79 vs. 1.14, P < 0.001), and Age SI (64.0 vs. 41.5, P < 0.001). The predictive power of the Age SI for in-hospital mortality was higher than SI (AUROC: 0.740 vs. 0.674, P < 0.001) or MSI (0.682, P < 0.001) in geriatric trauma patients.