The Effect of Emergency Medical Service Use and Inter-hospital Transfer on Prehospital Delay among Ischemic Stroke Patients: A Multicenter Observational Study.

The time between symptom onset and arrival at an emergency department (ED) (S2D) is a crucial time for optimal intravenous reperfusion care for ischemic stroke. We aimed to analyze the effect of emergency medical services (EMS) utilization and inter-hospital transfer on S2D in Korea. Ischemic stroke patients were prospectively enrolled from November 2007 to December 2012 in 23 tertiary and teaching hospital EDs in Korea. Of 31,443 adult ischemic stroke patients, 20,780 were categorized into 4 groups based on modes of EMS utilization and inter-hospital transfer: direct transport to destination ED by EMS (EMS direct; n=6,257, 30.1%), transfer after transport to another ED by EMS (EMS indirect; n=754, 3.6%), direct transport to the ED without using EMS (non-EMS direct; n=8,928, 43.0%), and transfer after visiting another hospital without using EMS (non-EMS indirect; n=4,841, 23.3%). Our primary outcome variable was of S2D within 2 hr (S2D ≤ 2 hr) and found that 30.8% of all patients and 52.3%, 16.4%, 25.9%, and 13.9% of EMS direct, EMS indirect, non-EMS direct, and non-EMS indirect, respectively, achieved S2D ≤ 2 hr. Adjusted odds ratio for S2D ≤ 2 hr were 6.56 (95% confidence interval [CI], 5.94-7.24), 2.27 (95% CI, 2.06-2.50), and 1.07 (95% CI, 0.87-1.33) for EMS direct, non-EMS direct, and EMS indirect, respectively. Patients directly transported to destination hospitals by the EMS show the highest proportion of therapeutic time window for optimal care in ischemic stroke.