Association Between Hospital Cardiac Management and Outcomes for Acute Myocardial Infarction Patients

BACKGROUND: Randomized trials have shown that medical and interventional therapies improve outcomes for acute myocardial infarction (AMI) patients. The extent to which hospital quality improvement translates into better patient outcomes is unclear. OBJECTIVES: To determine hospital cardiac management markers associated with improved outcomes. RESEARCH DESIGN, SUBJECTS: Population-based longitudinal cohort study of 98,115 adults hospitalized with first episode of AMI during 2000 to 2006 in 77 Ontario hospitals with >50 annual AMI admissions. MEASURES: Rates of 30-day and 1-year mortality, readmissions for AMI or death, and major cardiac events (readmissions for AMI, angina, heart failure, or death) within 6 months, according to index hospital cardiac management markers, including appropriate initial emergency department (ED) assessment (rate of high acuity triage) high-acuity and intensity of interventional (30-day cardiac catheterization rate) and medical (discharge statin prescribing rate) therapy. RESULTS: Thirty-day risk-adjusted mortality varied 2.3-fold (7.2%-16.9%) and major cardiac events rates varied 2-fold (18.2%-35.6%) across hospitals in 2006. Patients admitted to hospitals with the highest versus lowest rates of combined medical and interventional management had lower rates of 30-day mortality (adjusted relative rate aRR = 0.84, 95% CI, 0.78-0.91), 1-year mortality (aRR = 0.86, 0.81-0.91), AMI readmissions or death (aRR = 0.74, 0.69-0.78), and major cardiac event (aRR = 0.65, 0.61-0.68). Patients admitted to EDs with the highest rates of appropriate initial assessment had lower 30-day (aRR = 0.93, 0.88-0.98) and 1-year mortality (aRR = 0.96, 0.93-1.00). CONCLUSIONS: Hospitals with higher levels of both medical and interventional management and higher quality initial ED assessment had better outcomes. Readmissions were particularly sensitive to care processes. In the face of the unwarranted variations in outcomes across hospitals, strategies that promote better ED and inpatient management of AMI patients are needed.