Title : Shock index as clinical independent predictor of in-hospital mortality in acute coronary syndrome patients: A 5-year retrospective study
Abstract:
Introduction/Objective: In the Philippines, acute coronary syndrome (ACS) is a leading cause of mortality. Risk assessment is crucial for estimating prognosis and indicating the need for a more aggressive approach. Shock index (SI), ratio of heart rate and systolic blood pressure, is a bedside reflection of integrated response of the cardiovascular system. It is a simple yet powerful tool for prognosis in ACS. The study primarily aims to determine the correlation of shock index with clinical outcomes in ACS patients.
Methodology: This 5-year cross-sectional retrospective study was conducted in a tertiary hospital for patients aged 18 and above admitted for ACS from January 2018 to December 2022. Description of clinical profiles and clinical outcomes were noted. The study employed a multivariate regression analysis and receiver operating characteristic curve (ROC) analysis to determine the cut-off of shock index to predict in-hospital mortality.
Results/Analysis: Among the 926 patients included in the study, the population mainly composed of male, diabetics, hypertensive, dyslipidemia, and smoker patients with mean age of 60. Based on the multivariate logistic regression, it showed that shock index (p value of <0.001) is less than the level of significance (0.05). Therefore, high shock index is significantly associated with occurrence of inhospital mortality. The area under the ROC curve is 97.1%, which means that shock index is an excellent indicator of in-hospital mortality of patient. For shock index ≥ 0.8275, sensitivity is 89% and specificity of 93.2%.
Conclusion: Shock index is a simple, inexpensive, and readily available bedside marker that can be used in ACS patients. It only requires two routinely measured parameters without the need for specialized equipment. It proved to be a reliable parameter for predicting in-hospital mortality in ACS patients. This tool can be included in the risk stratification and can help in the decision making.
