Factors associated with use of emergency medical service for acute myocardial infarction in Beijing

Abstract

To examine the current ambulance transport rates and ascertain factors associated with use of emergency medical service (EMS) in patients with acute myocardial infarction (AMI) in Beijing. Between January 1 and December 31, 2006, a cross-sectional and multicenter survey was conducted in 19 hospitals in Beijing and included patients with ST-elevation myocardial infarction (STEMI) admitted within 24 hours of onset of symptoms. Data were collected by structured interviews and medical records review within 1 week after admission. Patients were categorized into the EMS group and the self-transport group according to their modes of transport to the initial hospital. Data were analyzed by descriptive statistics, univariate and multivariate logistic analysis. Of the 789 patients with STEMI, only 260 (33.0%) arrived at the initial hospital by EMS, while the remaining 529 (77.0%) relied on self-transport. Multivariate logistic analysis showed that age >/= 65 years (OR: 1.530, 95%CI: 1.050 - 2.230, P = 0.027), higher education level (OR: 2.032, 95%CI: 1.257 - 3.284, P = 0.004), history of coronary artery disease (OR: 0.474, 95%CI: 1.049 - 2.458, P = 0.029), unbearable symptoms (OR: 0.592, 95%CI: 1.090 - 2.520, P = 0.008), anxiety (OR: 0.760, 95%CI: 1.238 - 3.695, P = 0.006) and attribution of symptoms to cardiac origin (OR: 0.402, 95%CI: 1.020 - 2.171, P = 0.041) were independent predictors of EMS use. However, presence of pre-infarction angina significantly decreased the likelihood of using EMS (OR: 0.626, 95%CI: 0.431 - 0.907, P = 0.013). Only one-third of patients with STEMI arrived at the hospital by EMS in Beijing. Demographics, history of coronary artery disease, symptoms characteristics and cognitive factors of patients were associated with the EMS use.