Variation in revascularisation use and outcomes of patients in hospital with acute myocardial infarction across six high income countries: cross sectional cohort study

Abstract Objectives To compare treatment and outcomes for patients admitted to hospital with a primary diagnosis of ST elevation or non-ST elevation myocardial infarction (STEMI or NSTEMI) in six high income countries with very different healthcare delivery systems. Design Retrospective cross sectional cohort study. Setting Patient level administrative data from the United States, Canada (Ontario and Manitoba), England, the Netherlands, Israel, and Taiwan. Participants Adults aged 66 years and older admitted to hospital with STEMI or NSTEMI between 1 January 2011 and 31 December 2017. Outcomes measures The three categories of outcomes were coronary revascularisation (percutaneous coronary intervention or coronary artery bypass graft surgery), mortality, and efficiency (hospital length of stay and 30 day readmission). Rates were standardised to the age and sex distribution of the US acute myocardial infarction population in 2017. Outcomes were assessed separately for STEMI and NSTEMI. Performance was evaluated longitudinally (over time) and cross sectionally (between countries). Results The total number of hospital admissions ranged from 19 043 in Israel to 1 064 099 in the US. Large differences were found between countries for all outcomes. For example, the proportion of patients admitted to hospital with STEMI who received percutaneous coronary intervention in hospital during 2017 ranged from 36.9% (England) to 78.6% (Canada; 71.8% in the US); use of percutaneous coronary intervention for STEMI increased in all countries between 2011 and 2017, with particularly large rises in Israel (48.4-65.9%) and Taiwan (49.4-70.2%). The proportion of patients with NSTEMI who underwent coronary artery bypass graft surgery within 90 days of admission during 2017 was lowest in the Netherlands (3.5%) and highest in the US (11.7%). Death within one year of admission for STEMI in 2017 ranged from 18.9% (Netherlands) to 27.8% (US) and 32.3% (Taiwan). Mean hospital length of stay in 2017 for STEMI was lowest in the Netherlands and the US (5.0 and 5.1 days) and highest in Taiwan (8.5 days); 30 day readmission for STEMI was lowest in Taiwan (11.7%) and the US (12.2%) and highest in England (23.1%). Conclusions In an analysis of myocardial infarction in six high income countries, all countries had areas of high performance, but no country excelled in all three domains. Our findings suggest that countries could learn from each other by using international comparisons of patient level nationally representative data.


Ontario (Canada)
All hospitalizations for AMI in adults age > 66 years at the time of hospitalization during calendar years 2011-2017 were identified using the Discharge Abstract Database (DAD) for Ontario. Data from 2010 were used as a "look-back" and data from 2018 were used to ascertain post-AMI outcomes.
The DAD includes all admissions to all acute care hospitals in the province of Ontario and thus is inclusive of the entire Ontario population.
Datasets used in the analyses were linked using unique encoded identifiers and analyzed at ICES. ICES is an independent, non-profit research institute whose legal status under Ontario's health information privacy law allows it to collect and analyze health care and demographic data, without consent, for health system evaluation and improvement. 6

AMI Identification and Outcomes
Data source 2 Use Discharge Abstract Database (Ontario), Canadian Institute for Health Information (2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018) a. Identification of patients hospitalized with a primary diagnosis of AMI 7 8 b. Creation of comorbidities c. In-hospital outcomes OHIP Billing Data (2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018) a. Post-AMI treatments and procedures Registered Persons Data Base files a. Determination of death date, birth date, and insurance coverage start and end date Population Count and Demographics (Used for Calculation of AMI Hospitalization Rates and Standardization) Registered Persons Data Base files Age/sex/ethnicity/area of residence information The use of the data in this project is authorized under section 45 of Ontario's Personal Health Information Protection Act (PHIPA) and does not require review by a Research Ethics Board.
The analyses, conclusions, opinions and statements expressed herein are solely those of the authors and do not reflect those of the funding or data sources; no endorsement is intended or should be inferred.

Manitoba (Canada)
All hospitalizations for AMI in adults age > 66 years at the time of hospitalization during calendar years 2011-2017 were identified using 100% Manitoba Discharge Abstract Database (DAD). Data from 2010 was used as a "look-back" and data from 2018 were used to ascertain post-AMI outcomes.
The Manitoba DAD includes all admissions to all acute care hospitals in the province of Manitoba and thus is inclusive of the entire Manitoba population eligible to receive health services.
Analyses were conducted using the Population Research Data Repository housed at the Manitoba Centre for Health Policy and utilized the administrative data from the Manitoba ministry of health (I.e., Manitoba Health and Seniors Care). The administrative data captures all publicly-insured health services for all residents of the province who are eligible to receive health services. All hospitalizations for AMI in adults age > 66 years at the time of hospitalization during calendar years 2011-2017 were identified using the Clinical Practice Research Datalink. Data from 2010 was used as a "look-back" and data from 2018 were used to ascertain post-AMI outcomes. CPRD has been shown to be representative of the English population by age, sex and ethnicity, and validated for research. [9][10][11] Analyses were conducted at the Institute of Health Informatics, University College London using linked electronic health records from primary care (CPRD), hospitalisation (HES) and the national death registry (ONS). 10

Netherlands
All hospitalizations for AMI in Dutch adults age > 66 years at the time of hospitalization during calendar years 2013-2017 were identified using data from the national register for hospital care. 13 Data from 2012 was used as a "look-back" and data from 2018 were used to ascertain post-AMI outcomes.
These data include all inpatient hospitalizations for the Netherlands. Primary and secondary diagnosis are recorded as well as the main procedure performed during the admission. Demographic information and, if applicable, date of death, were extracted from municipality registers 4 .

Israel
Analyses were conducted at the Clinical Research Center in Soroka University Medical Center and included national data of Clalit Health Services insured patients.
All hospitalizations for AMI in adults age > 66 years at the time of hospitalization during calendar years 2011-2017 were identified using Clalit Health Services (CHS) Data sharing platform powered by MDClone © (https://www.mdclone.com). 16 Data from 2010 was used as a "look-back" and data from 2018 were used to ascertain post-AMI outcomes. The data is broadly representative of the Israel population with respect to age, sex, and geography. Clalit Health Services is Israel's largest insurance company and health care provider, providing most of Israel's health care services and providing health insurance to 54% of the country's population. 14 Services include primary, secondary, and tertiary care (including a third of Israel's acute care beds), as well as pharmacies and paramedical services. CHS maintains a comprehensive database, continuously updated with information about a subject's demographics, community and outpatient visits, laboratory tests, hospitalizations, medication prescriptions, and purchases.