Shock Index is a Stronger Predictor of Outcomes in Older Compared to Younger Patients

Abstract

Introduction: The shock index (SI) is a known predictor of unfavorable outcomes in trauma. This study seeks to examine and compare the SI values between geriatric patients and younger adults.

Methods: We conducted a retrospective study of the Trauma Quality Improvement Program database from 2017 to 2019. All patients≥ 25 y with injury severity score ≥ 16 were included. Age groups were defined as 25-44 y (group A), 45-64 y (group B), and ≥65 y (group C). SI was calculated for all patients. The primary outcome was mortality and secondary outcomes were need for blood transfusion and need for major surgical intervention (consisting angiography, exploratory laparotomy, and thoracotomy).

Results: A total of 244,943 patients were studied. The SI was highest in group A (0.82 ± 0.33) and lowest in group C (0.62 ± 0.30) (P < 0.001). Mortality rate of group C (17%) was significantly higher than group A (9.7%) and B (11.3%) (P < 0.001). In group A, each 0.1 increase in SI was associated with mortality (odds ratio [OR] = 1.079), need for blood transfusion (OR = 1.225) and need for major surgical intervention (OR = 1.347) (P < 0.001 for all). In group C, each 0.1 increase in SI was associated with mortality (OR = 1.126), need for blood transfusion (OR = 1.318), and need for major surgical intervention (OR = 1.648) (P < 0.001 for all). The area under the curve of SI was significantly higher in group C compared to other groups for needing a major surgical intervention and need for blood transfusion (P < 0.05 for both).

Conclusions: These results highlight the significance of the SI as a valuable indicator in geriatric patients with severe trauma. The findings show that SI predicts outcomes in geriatrics more strongly than in younger counterparts.

Keywords: Outcomes; Shock; Shock index; Trauma.