Etiology of Shock in the Emergency Department: A 12-Year Population-Based Cohort Study

Abstract

Introduction: The knowledge of the etiology and associated mortality of undifferentiated shock in the emergency department (ED) is limited. We aimed to describe the etiology-based proportions and incidence rates (IR) of shock, as well as the associated mortality in the ED.

Methods: Population-based cohort study at a University Hospital ED in Denmark from January 1, 2000, to December 31, 2011. Patients aged ≥18 years living in the ED-catchment area (N = 225,000) with a first-time ED presentation with shock (n = 1,553) defined as hypotension (systolic blood pressure ≤100 mm Hg) and ≥1 organ failures were included. Discharge diagnoses defined the etiology and were grouped as follows: distributive septic shock (SS), distributive non-septic shock (NS), cardiogenic shock (CS), hypovolemic shock (HS), obstructive shock (OS), and other conditions (OC). Outcomes were etiology-based characteristics, annual IR per 100,000 person-years at risk (95% confidence intervals [CIs]), mortality at 0 to 7-, and 0 to 90 days (95% CIs) and hazard rates (HR) at 0 to 7, 8 to 90 days (95% CIs). Poisson and Cox regression models were used for analyses.

Results: Among 1,553 shock patients: 423 (27.2%) had SS, 363 (23.4%) NS, 217 (14.0%) CS, 479 (30.8%) HS, 14 (0.9%) OS, and 57 (3.7%) OC. The corresponding IRs were 16.2/100,000 (95% CI: 14.8-17.9), 13.9/100,000 (95% CI: 12.6-15.4), 8.3/100,000 (95% CI: 7.3-9.5), 18.4/100,000 (95% CI: 16.8-20.1), 0.5/100,000 (95% CI: 0.3-0.9), and 2.2/100,000 (95% CI: 1.7-2.8). SS IR increased from 8.4 to 28.5/100,000 during the period 2000 to 2011. Accordingly, the 7-, and 90-day mortalities of SS, NS, CS, and HS were 30.3% (95% CI: 25.9-34.7) and 56.2% (95% CI: 50.7-61.5), 12.7% (95% CI: 9.2-16.1) and 22.6% (95% CI: 18.1-27.7), 34.6% (95% CI: 28.2-40.9) and 52.3% (95% CI: 44.6-59.8), 19.2% (95% CI: 15.7-22.7), and 36.8% (95% CI: 33.3-43.3). SS (HR = 1.46 [95% CI: 1.03-2.07]), and CS (HR = 2.15 [95% CI: 1.47-3.13]) were independent predictors of death within 0 to 7 days, whereas SS was a predictor within 8 to 90 days (HR = 1.66 [95% CI: 1.14-2.42]).

Conclusion: HS and SS are frequent etiological characteristics followed by NS and CS, whereas OS is a rare condition. We confirm the increasing trend of SS, as previously reported. Seven-day mortality ranged from 12.7% to 34.6%, while 90-day mortality ranged from 22.6% to 56.2%. The underlying etiology was an independent predictor of mortality.

Fig. 1

Flow chart of patients recruited to the study.

Fig. 2

Crude annual incidence rates of shock from 2000 to 2011 stratified on etiology (septic, non-septic, hypovolemic, cardiogenic, obstructive, and other).

Fig. 3

Crude incidence rates stratified by age and etiology.

Fig. 4

Kaplan–Meier curves illustrating overall 90-day survival across etiologies of shock.

Fig. 5

Annual proportion of shock patients based on the annual overall ED visits of adult patients (age ≥18 years).