Berger Presentation, Workshop Lisbon 13th December

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International Comparison of Acute
Myocardial Infarction Health Care
Minneapolis‐St. Paul, Minnesota vs. Goteborg, Sweden
Alan Berger, MD, MPH
Associate Professor of Medicine
University of Minnesota
December 11th, 2014
Cardiovascular Epidemiology
Study Design
Study Design Traditional and
Novel Risk
Factor and
Models
Treatment
Effect
Treatment
Effectiveness
Impact on
Public Policy
(Real World)
Clinical
Trial
X
Prospective
Cohort
X X X X
Retrospective
Survey
X X X

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Wong, ND. Nat. Rev. Cardiol. 2014. doi:10.1038/nrcardio.2014.26
Global & National Cardiovascular Epidemiologic Studies
Wong, ND. Nat. Rev. Cardiol. 2014. doi:10.1038/nrcardio.2014.26
Global & National Cardiovascular Epidemiologic Studies

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• Most of our good ideas (i.e., hypothesis generation) have come from
population comparisons
• Lack of variation of exposure within high income countries
• Lack of generalizability between high income and low income
countries
• Lack of exposure in high income countries
• Importance of addressing the most important public health problems
on a global basis.
International Collaboration in Epidemiology
Primary Reasons
Pearce N. OA Epidemiology 2013 Oct 01;1(2):15.
Minneapolis – St. Paul, MN and Goteborg, Sweden
Demographics
2000 population: 2,642,056
≥ 75 years: 44,243 men, 81,249 women
Mainly white and of northern European descent
2002 population: 474,572
≥ 75 years: 14,752 men, 26,024 women
Ethnic Swedes: 81%

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• Russell Luepker
• Alan Berger
• Angela Vargas
• Kathy Doliszny
• Paul McGovern
• Susan Duval
• Lindsay Smith
• James Pankow
• Eyal Shahar
• Seungmin Lee
• Johan Herlitz
• Thomas Karlsson
• Gunar Brandrup‐Wognsen
• Ann‐Marie Svensson
• Mikael Dellborg
• Putte Abrahamsson
• Bjorn Karlson
Minneapolis – St. Paul, MN and Goteborg, Sweden
International Collaboration
Minneapolis – St. Paul, Minnesota Goteborg, Sweden
• Category A (ESC/ACC/AHA/WHF)
• (+) Cardiac biomarker + [Symptoms or Q Waves or ST Depression or STEMI or Positive Imaging]
• Unexpected cardiac death with symptoms + [Q waves or ST depression or STEMI or Thrombus]
• Autopsy evidence
• Category B (cardiac biomarkers absent):
• Symptoms + Q waves
• Death with Hx CHD and Symptoms within 72 hours
• Category C (Probable MI):
• Symptoms + [Q waves of lower probability using Minnesota Code or incomplete biomarkers]
• Inconclusive autopsy
Mendis S, et al. International Journal of Epidemiology 2011;40:139–146

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• How does evolution in AMI definition impact on prevalence / incidence of AMI?
• How does evolution of technology – more sensitive and specific cardiac
biomarkers – impact on prevalence / incidence of AMI?
Mendis S, et al. International Journal of Epidemiology 2011;40:139–146
• Objective: Identify countries with similar demographics / economics
but different processes of care to assess whether variation in practice
impacts outcomes
• Sampling scheme
• Ensure study samples are similar between countries
• Ensure completion of study samples
• Ensure accuracy of data collection
• Outcome assessment
• Identify endpoints of mutual interest
• Validate outcomes
Minneapolis – St. Paul, MN and Goteborg, Sweden
International Collaboration

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• Project Development
• Face‐to‐face meetings
• Shared effort in regard to methodology & statistical analyses
• Publications
• Discuss authorship at early stages
• Scope of project spawns many ideas and opportunities
Minneapolis – St. Paul, MN and Goteborg, Sweden
International Collaboration
• Time frame: On average, every 5 years
• Study Population
• Minnesota
• Computerized list of AMIs generated by each hospital
• Random sample of AMI hospitalizations (ICD‐9 code 410) was selected
• Additional sample of UA hospitalizations (ICD‐9 code 411), some of which were AMI
• Sampling ranged from 50% to 100% of patients depending on survey year
• Sweden
• All AMI hospitalizations
• Repeat hospitalizations during same year excluded
Minneapolis – St. Paul, MN and Goteborg, Sweden
Study Sampling

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• Definition of Acute Myocardial Infarction (AMI)
• Chest Pain
• ECG indicative of AMI
• Positive cardiac biomarker (CK‐MB > 2 x ULN, troponin > 2 x ULN)
• Impact of Technologic Advancement
• Symptoms & ECG stable
• Cardiac biomarkers change with increasing sensitivity and specificity
• Technology impacts case definitions, and, hence incidence of disease
Minneapolis – St. Paul, MN and Goteborg, Sweden
AMI Definition
• Minneapolis – St. Paul, Minnesota
• Acute care hospitals (N = 22), 21 participated in survey, 1 small rural hospital refused
• All of the participating hospitals had intensive care units for AMI treatment
• Cardiologists provided care in most hospitals
• Cardiac catheterization / PCI available at 12 hospitals and these hospitals accounted
for 76% of primary AMI admissions
• Goteborg, Sweden
• Two acute care hospitals (Sahlgren’s Hospital and Ostra Hospital), each serving half of
the city, both of which participated.
• Most patients admitted to CCU and received treatment from fully trained
cardiologists, cardiologists in training, or internal medicine physicians doing required
6‐month cardiology training.
• Cardiac catheterization / PCI performed at both facilities, only one provided those
services 24 hrs a day, 7 days a week. Transfer to that hospital was readily available.
Minneapolis – St. Paul, MN and Goteborg, Sweden
Hospital Facilities

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• Readily accessible
• Limited training
• Scope of data limited
• Depth of data limited
• Requires validation
Minneapolis – St. Paul, MN and Goteborg, Sweden
International Collaboration
• Time consuming
• Abstractors require training
• Increased scope of data
• Increased depth of data
• Requires validation
Administrative Data Chart Abstraction
AMI Surveys
Abstraction System

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• Trained nurses
• Supervised by physicians
• Inter‐observer variability assessed by random re‐abstraction of charts
• Data Elements
• Past medical history
• Symptoms
• Signs
• Laboratory data (CK‐MB, troponin)
• ECGs
• Cardiac procedures
• Pharmacotherapy
• Complications
AMI Surveys
Chart Abstraction
• Laptop Computers
• Portability
• Security
• Access Database
• Multi‐user, capable of synchronizing users
• Easy to navigate (tabbed forms, check boxes, drop down selections)
• Error checking
• Ability to annotate
• Paper Documentation
• ECGs
• Diagnostic Reports (X Ray, ECG, Coronary Angiogram, PCI, CABG)
AMI Surveys
Abstraction Instrument

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• Manual of Operations
• Document Format
• Paper: Prepare abstractors for process and work flow
• Electronic: Rapidly accessible definitions
• Content
• All variables well defined
• Identify which variable to abstract when multiple are available
• Documentation must be able to handle “what if” situations
AMI Surveys
Abstraction Instrument
• In‐hospital
• Obtained from the medical record.
• After hospital discharge, vital status obtained and after hospital discharge
from computer linkage with death certificate files provided by the Minnesota
Department of Health and the Swedish National Registry
• Minnesota Department of Health has complete death certificate records
• Sweden: Survival confirmation as well as date of death for those who died were obtained
from the Swedish National Population Registry.
AMI Surveys
Vital Status

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• Recognition of importance of identifying trends
• Incidence of AMI
• Trends in treatment
• Pharmacologic therapies
• Diagnostic and Interventional procedures
• Case fatality
• Data Collection
• EMR permits more detailed and complete access to records
• EMR allows remote access to data
Cardiovascular Epidemiologic Studies
Current Opportunities
• Health Insurance Portability and Accountability Act (HIPAA)
• Constraints on access to records
• Patients have right to opt out of studies if identified information
• Large observational studies costly
• Resources for data abstraction
Cardiovascular Epidemiologic Studies
Current Barriers

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Comparison of treatment and outcomes
for patient with acute myocardial infarction
in Minneapolis‐St. Paul, Minnesota and
Goteborg, Sweden
Mcgovern PG, et al. Am J Cardiol 1997; 80: 557‐62.
Age‐Specific Rates for 1990 per 100,000 Persons for CHD
Mortality and Hospitalized AMI in Goteborg and MSP
Mcgovern PG, et al. Am J Cardiol 1997; 80: 557‐62.
Age‐adjusted CHD
mortality lower for both
men and women in MSP
than Goteborg.
Age‐adjusted hospitalized
AMI discharge rate higher
for both men and women
in Goteborg than MSP.

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Mcgovern PG, et al. Am J Cardiol 1997; 80: 557‐62.
Baseline Characteristics of AMI Patients
Goteborg (1990‐1991) vs. MSP (1990)
Early studies showed a marked difference in the use of both diagnostic procedures and
coronary revascularization (PCI & CABG), with rates higher in MSP than Goteborg.
Mcgovern PG, et al. Am J Cardiol 1997; 80: 557‐62.
Baseline Characteristics of AMI Patients
Goteborg (1990‐1991) vs. MSP (1990)
Early data also showed difference in the use of what are now considered standard AMI
pharmacotherapies.

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Mcgovern PG, et al. Am J Cardiol 1997; 80: 557‐62.
Baseline Characteristics of AMI Patients
Goteborg (1990‐1991) vs. MSP (1990)
Early data showed differences in post MI survival, more evident in men than women.
International comparison of treatment and
long‐term outcomes for acute myocardial
infarction in the elderly:
Minneapolis/St. Paul, MN, USA and
Goteborg, Sweden
Smith LG, et al. European Heart Journal (2013) 34, 3191–3197.

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AMI Therapies: MSP vs. Goteborg
2001 Survey
Smith LG, et al. European Heart Journal (2013) 34, 3191–3197.
Increase use of aspirin, ACE‐I, nitrates, and additional
antiplatelet agents in MSP compared to Goteborg.
Increased use of beta blockers in Goteborg compared to MSP.
AMI Therapies: MSP vs. Goteborg
2001 Survey
Smith LG, et al. European Heart Journal (2013) 34, 3191–3197.
ST elevation MI more common in Goteborg than MSP. In spite of this, patients in MSP more
likely to undergo coronary angiography and PCI than patients treated In Goteborg. Among
patients undergoing PCI, the use of early intervention was similar between both countries.

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AMI Discharge Therapies: MSP vs. Goteborg
2001 Survey
Smith LG, et al. European Heart Journal (2013) 34, 3191–3197.
At discharge, ACE‐I, nitrates, additional antiplatelet agents, and statins were more likely to
be prescribed in MSP compared to Goteborg. Beta blockers were more likely to be
prescribed at discharge in Goteborg compared than MSP.
AMI Male Survival: MSP vs. Goteborg
2001 Survey
Smith LG, et al. European Heart Journal (2013) 34, 3191–3197.
Survival in both men and women was improved following an AMI in MSP compared to
Goteborg. The survival curves began to diverge in the first year and continued to separate
over the subsequent 7 years.

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Adjusted AMI Survival: MSP vs. Goteborg
2001 Survey
Smith LG, et al. European Heart Journal (2013) 34, 3191–3197.
• Svensson AM, et al. The influence of a history of diabetes on
treatment and outcome in acute myocardial infarction, during two
time periods and in two different countries. International Journal of
Cardiology (2007) 119: 310‐25.
• Vargas A,et al. Characteristics and outcomes among patients
undergoing coronary artery bypass grafting in western Sweden and
Minneapolis–St Paul, Minnesota. Am Heart J 2001; 142: 1080‐7.
• Herlitz J, et al. Comparison of treatment and outcomes for patients
with acute myocardial infarction in Minneapolis/St. Paul, Minnesota,
and Goteborg, Sweden. Am Heart J 2003; 146: 1023‐9.
Minneapolis – St. Paul, MN and Goteborg, Sweden
Other Published Work