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Comparison of hospital variation in acute myocardial infarction care and outcome between Sweden and United Kingdom: population based cohort study using nationwide clinical registries

BMJ 2015; 351 doi: (Published 07 August 2015) Cite this as: BMJ 2015;351:h3913
  1. Sheng-Chia Chung, research associate1,
  2. Johan Sundström, professor2, scientific director3,
  3. Chris P Gale, associate professor4,
  4. Stefan James, professor2, scientific director3,
  5. John Deanfield, professor5,
  6. Lars Wallentin, senior professor2, professor3,
  7. Adam Timmis, professor6,
  8. Tomas Jernberg, associate professor7,
  9. Harry Hemingway, professor and director1
  10. on behalf of SWEDEHEART/RIKS-HIA (Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies/Register of Information and Knowledge about Swedish Heart Intensive care Admissions), NICOR/MINAP (National Institute for Cardiovascular Outcomes Research/Myocardial Ischaemia National Audit Project), and CALIBER (CAardiovascular disease research using linked bespoke studies and electronic health records)
  1. 1Farr Institute of Health Informatics Research and Institute of Health Informatics, University College London, London NW1 2DA, UK
  2. 2Department of Medical Sciences, Cardiology, Uppsala University, Uppsala, Sweden
  3. 3Uppsala Clinical Research Center, Uppsala, Sweden
  4. 4Cardiovascular Health Sciences, University of Leeds, Leeds, UK
  5. 5National Centre for Cardiovascular Prevention and Outcomes, London, UK
  6. 6National Institute for Health Research, Cardiovascular Biomedical Research Unit, Bart’s Health London, London, UK
  7. 7Department of Medicine, Huddinge, Section of Cardiology, Karolinska Institute, Stockholm, Sweden
  1. Correspondence to: Sheng-Chia Chung s.chung{at}
  • Accepted 11 July 2015


Objective To assess the between hospital variation in use of guideline recommended treatments and clinical outcomes for acute myocardial infarction in Sweden and the United Kingdom.

Design Population based longitudinal cohort study using nationwide clinical registries.

Setting and participants Nationwide registry data comprising all hospitals providing acute myocardial infarction care in Sweden (SWEDEHEART/RIKS-HIA, n=87; 119 786 patients) and the UK (NICOR/MINAP, n=242; 391 077 patients), 2004-10.

Main outcome measures Between hospital variation in 30 day mortality of patients admitted with acute myocardial infarction.

Results Case mix standardised 30 day mortality from acute myocardial infarction was lower in Swedish hospitals (8.4%) than in UK hospitals (9.7%), with less variation between hospitals (interquartile range 2.6% v 3.5%). In both countries, hospital level variation and 30 day mortality were inversely associated with provision of guideline recommended care. Compared with the highest quarter, hospitals in the lowest quarter for use of primary percutaneous coronary intervention had higher volume weighted 30 day mortality for ST elevation myocardial infarction (10.7% v 6.6% in Sweden; 12.7% v 5.8% in the UK). The adjusted odds ratio comparing the highest with the lowest quarters for hospitals’ use of primary percutaneous coronary intervention was 0.70 (95% confidence interval 0.62 to 0.79) in Sweden and 0.68 (0.60 to 0.76) in the UK. Differences in risk between hospital quarters of treatment for non-ST elevation myocardial infarction and secondary prevention drugs for all discharged acute myocardial infarction patients were smaller than for reperfusion treatment in both countries.

Conclusion Between hospital variation in 30 day mortality for acute myocardial infarction was greater in the UK than in Sweden. This was associated with, and may be partly accounted for by, the higher practice variation in acute myocardial infarction guideline recommended treatment in the UK hospitals. High quality healthcare across all hospitals, especially in the UK, with better use of guideline recommended treatment, may not only reduce unacceptable practice variation but also deliver improved clinical outcomes for patients with acute myocardial infarction.

Clinical trials registration Clinical trials NCT01359033.


  • Contributors: SCC analysed the data. All authors contributed to the preparation and content of the manuscript. Giovanna Ceroni from the Farr Institute, London, provided additional editorial support. The study investigators are solely responsible for the design and conduct of this study and its final contents. SCC is the guarantor.

  • Funding: This study has been supported by the European Implementation Score project, funded by the EU 7th Framework Programme (grant agreement 223153), National Institute for Health Research (programme grant RP-PG-0407-10314), Wellcome Trust (086091/Z/08/Z), Medical Research Council Population Health Scientist Fellowship (S-CC: grant MR/M015084/1), and Medical Research Council Prognosis Research Strategy (PROGRESS) Partnership (G0902393/99558) (HH, AT) and by awards to establish the Farr Institute of Health Informatics Research, London, from the Medical Research Council, Arthritis Research UK, British Heart Foundation, Cancer Research UK, Chief Scientist Office, Economic and Social Research Council, Engineering and Physical Sciences Research Council, National Institute for Health Research, National Institute for Social Care and Health Research, and Wellcome Trust (S-CC). AT acknowledges the support of Barts and the London Cardiovascular Biomedical Research Unit, funded by the National Institute for Health Research. The Swedish Heart Lung Foundation (JS, TJ, and SJ) and the Swedish Research Council (JS: grants 2007-5942 and 2010-1078) supported the study. The sponsors had no role in the study design, the data collection, analysis, and interpretation, or the writing of the report.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at (available on request from the corresponding author) and declare: no support from any organisation for the submitted work other than those acknowledged above; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: The study was approved by the MINAP Academic Group and the Steering Group of SWEDEHEART.

  • Data sharing: Details of how to obtain additional data from the study (such as technical appendix, statistical programming) are available from the corresponding author at s.chung{at}

  • Transparency declaration: The lead author (the manuscript’s guarantor) affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

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