title: Comparison of outcomes of ambulance users and nonusers in ST elevation myocardial infarction.
abstract: In a systematic province-wide evaluation of care and outcomes of ST elevation myocardial infarction (STEMI), we sought to examine whether a previously documented association between ambulance use and outcome remains after control for clinical risk factors. All 82 acute care hospitals in Quebec (Canada) that treated at least 30 acute myocardial infarctions annually participated in a 6-month evaluation in 2008 to 2009. Medical record librarians abstracted hospital chart data for consecutive patients with a discharge diagnosis of myocardial infarction who presented with characteristic symptoms and met a priori study criteria for STEMI. Linkage to administrative databases provided outcome data (to 1 year) and co-morbidities. Of 1,956 patients, 1,222 (62.5%) arrived by ambulance. Compared with nonusers of an ambulance, users were older, more often women, and more likely to have co-morbidities, low systolic pressure, abnormal heart rate, and a higher Thrombolysis In Myocardial Infarction risk index at presentation. Ambulance users were less likely to receive fibrinolysis or to be sent for primary angioplasty (78.5% vs 83.2% for nonusers, p = 0.01), although if they did, treatment delays were shorter (p <0.001). The 1-year mortality rate was 18.7% versus 7.1% for nonusers (p <0.001). Greater mortality persisted after adjusting for presenting risk factors, co-morbidities, reperfusion treatment, and symptom duration (hazard ratio 1.56, 95% confidence interval 1.30 to 1.87). In conclusion, ambulance users with STEMI were older and sicker than nonusers. Mortality of users was substantially greater after adjustment for clinical risk factors, although they received faster reperfusion treatment overall.
authors.affiliation: Cardiology Evaluation Unit, Institut national d'excellence en santé et en services sociaux, Montreal, Quebec, Canada. Electronic address: lucy.boothroyd@inesss.qc.ca.
authors.forename: Lucy J
authors.initials: LJ
authors.lastname: Boothroyd
authors.affiliation: Cardiology Evaluation Unit, Institut national d'excellence en santé et en services sociaux, Montreal, Quebec, Canada.
authors.forename: Laurie J
authors.initials: LJ
authors.lastname: Lambert
authors.affiliation: Emergency Department, Sir Mortimer B. Davis Jewish General Hospital, Montreal, Quebec, Canada; Corporation d'Urgences-santé, Montreal, Quebec, Canada.
authors.forename: Eli
authors.initials: E
authors.lastname: Segal
authors.affiliation: Corporation d'Urgences-santé, Montreal, Quebec, Canada; Services préhospitaliers d'urgence en Montérégie, Longueuil, Quebec, Canada; Département de médecine préhospitalière, Hôpital Sacré-Cœur de Montréal, Montreal, Quebec, Canada.
authors.forename: Dave
authors.initials: D
authors.lastname: Ross
authors.affiliation: Service de cardiologie, Centre hospitalier régional de Lanaudière, Joliette, Quebec, Canada.
authors.forename: Simon
authors.initials: S
authors.lastname: Kouz
authors.affiliation: Service de l'urgence, Centre hospitalier affilié universitaire Hôtel-Dieu de Lévis, Levis, Quebec, Canada.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Maire
authors.affiliation: Service de cardiologie, Centre hospitalier universitaire de Sherbrooke, Sherbrooke, Quebec, Canada.
authors.forename: Richard
authors.initials: R
authors.lastname: Harvey
authors.affiliation: Cardiology Evaluation Unit, Institut national d'excellence en santé et en services sociaux, Montreal, Quebec, Canada.
authors.forename: Yongling
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: Cardiology Evaluation Unit, Institut national d'excellence en santé et en services sociaux, Montreal, Quebec, Canada.
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Brown
authors.affiliation: Division of Cardiology, St. Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: James
authors.initials: J
authors.lastname: Nasmith
authors.affiliation: Cardiology Evaluation Unit, Institut national d'excellence en santé et en services sociaux, Montreal, Quebec, Canada; Département multidisciplinaire de cardiologie, Institut universitaire de cardiologie et de pneumologie de Québec, Quebec, Canada.
authors.forename: Peter
authors.initials: P
authors.lastname: Bogaty
mesh_terms: D000368:Aged; D000552:Ambulances / Q000706:statistics & numerical data*; D004562:Electrocardiography; D004632:Emergency Medical Services / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy*; D011792:Quebec / Q000453:epidemiology; D012189:Retrospective Studies