Modified Shock Index (MSI) as a Predictor for Mortality and Hospitalization Among Patients with Dementia

Background

As life expectancy increases worldwide, the number of elderly patients (65 years old or older) is rising. One out of four elderly patients in the Emergency Department (ED) suffers from significant cognitive impairment creating great difficulty in determining the urgency of patients` cases as well as in diagnosis and decision-making processes.

Modified Shock Index (MSI) < 0.7 or > 1.3, created as the ratio of HR and mean artery pressure (MAP), was found to be a valuable clinical predictor of mortality when applied on patients in the ED.

Objective

This paper examines the MSI as a predictor for mortality and hospitalization among patients with dementia in the ED unit.

Our goal is to establish a tool for the ED physician for determining whether to hospitalize or discharge a patient with dementia.

Methods

All patients 65 years old or older with dementia admitted to the ED at Soroka University Medical Center between the years 2014-2017 were included in this paper. Demographic, clinical and hospitalization data, such as Charlson Comorbidity Index (CCI) score, date of death and hospitalization duration, were all collected from computerized databases. The MSI score was calculated for each patient individually and the data was divided into three groups, in accordance with the literature: MSI < 0.7; 0.7>MSI<1.3; MSI>1.3.

We conducted a logistic regression as a predictor of death within 30 days from arrival to the ED, as well as a Cox analysis for the numbers of days till death and a binominal regression for the prediction of number days of admission.

Results

We included 1,437 patients, 36% of whom were male (661 patients), diagnosed with a severe cognitive disorder, with the mean age of 83 ± 6.8 years old.

All regressions were adjusted according to age, gender and CCI score, showing a statistically significant difference between each MSI group. Demonstrating a higher mortality rate with correlation to a higher MSI score.

Conclusions

Patients with an MSI score higher than 1.3 were at higher risk of death within 30 days of arrival to the ED, fewer days until death and more days in admission. This finding is a reliable/strong indicator for the mortality rate in demented patients 65 years old or older.