Long-term mortality of patients with acute myocardial infarction in the United States and Canada: comparison of patients enrolled in Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO)-I.
BACKGROUND
In a previous substudy of the GUSTO-I trial, we observed better functional and quality-of-life outcomes among patients in the United States (US patients) compared with patients in Canada. Rates of invasive therapy were significantly higher in the United States and were associated with a small mortality benefit (0.4%, adjusted P=0.02). We sought to determine whether Canadian-US differences in practice patterns in GUSTO-I had an impact on 5-year mortality.


RESULTS
Mortality data for 23,105 US and 2898 Canadian patients enrolled in GUSTO-I were obtained from national mortality databases. Median follow-up was 5.46 years in the US and 5.33 years in the Canadian cohort. Five-year mortality rate was 19.6% among US and 21.4% among Canadian patients (P=0.02). After baseline adjustment, enrollment in Canada was associated with a higher hazard of death (1.17; 95% confidence interval, 1.07 to 1.28, P=0.001). Revascularization rates during the index hospitalization in the United States were almost 3 times those in Canada: 30.5% versus 11.4% for angioplasty and 13.1% versus 4.0% for bypass surgery (P<0.01 for both). After accounting for revascularization status as a time-dependent covariate, country was no longer a significant predictor of long-term mortality. These results were confirmed in a propensity-matched analysis.


CONCLUSIONS
Our results suggest, for the first time, that the more conservative pattern of care with regard to early revascularization in Canada for ST-segment elevation acute myocardial infarction may have a detrimental effect on long-term survival. Our results have important policy implications for cardiac care in countries and healthcare systems wherein use of invasive procedures is similarly conservative.
Kaul
Padma
P
University of Alberta, 7221 Aberhart Center I, 8440 112 St, Edmonton, AB T6G 2B7, Canada. pkaul@ualberta.ca
Armstrong
Paul W
PW
Chang
Wei-Ching
WC
Naylor
C David
CD
Granger
Christopher B
CB
Lee
Kerry L
KL
Peterson
Eric D
ED
Califf
Robert M
RM
Topol
Eric J
EJ
Mark
Daniel B
DB
D000368:Aged; D017130:Angioplasty / Q000706:statistics & numerical data; D000925:Anticoagulants / Q000008:administration & dosage / Q000627:therapeutic use; D002170:Canada / Q000453:epidemiology; D019090:Case Management; D015331:Cohort Studies; D015897:Comorbidity; D001026:Coronary Artery Bypass / Q000706:statistics & numerical data; D004359:Drug Therapy, Combination; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D005500:Follow-Up Studies; D006493:Heparin / Q000008:administration & dosage / Q000627:therapeutic use; D006801:Humans; D007275:Injections, Intravenous; D007279:Injections, Subcutaneous; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy / Q000401:mortality* / Q000601:surgery / Q000628:therapy; D009204:Myocardial Revascularization / Q000379:methods / Q000706:statistics & numerical data; D010818:Practice Patterns, Physicians'; D016016:Proportional Hazards Models; D013300:Streptokinase / Q000627:therapeutic use; D016019:Survival Analysis; D015912:Thrombolytic Therapy / Q000706:statistics & numerical data; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology
D000925:Anticoagulants; D005343:Fibrinolytic Agents; D006493:Heparin; D013300:Streptokinase; D010959:Tissue Plasminogen Activator