Re: Determinants of the decline in mortality from acute myocardial infarction in England between 2002 and 2010: linked national database study
Smolina and colleagues (Jan 27th) used person-linked hospital and mortality data to investigate the remarkable decline in mortality from coronary heart disease that happened in England between 2002 and 2010. They found that age standardised mortality had fallen by about one half while event rates and case fatality had both declined by about one third. About one half of the mortality decline was due to reduced case fatality and about one half to fewer cases.
These conclusions agree with those of other authors (1-3) but there still remain several important and unanswered questions. What is behind the reduced case fatality? Better treatment (primary angioplasty, use of defibrillation, reduction in treatment delay)?; or reduced disease severity (fewer ST elevation infarctions, changed definition to include cases previously classified as unstable angina and not infarction)? What is behind the reduction in case numbers? Better primary and/or secondary prevention?
The original MONICA Study (4) and our own UK Heart Attack Study (5,6), which was performed a decade later, examined individual case records and/or circumstances of death and autopsy records of victims of out-of-hospital cardiac death. These earlier studies were able to put some ‘clinical flesh’ on the ‘statistical bones’. Any attempt to obtain further insights into how the remarkable decline in mortality has occurred will require the same degree of individual case analysis as in these earlier studies.
(1) Tunstall-Pedoe H, Vanuzzo D, Hobbs M et al. Estimation of contribution of changes in coronary care to improving survival, event rates and coronary heart disease mortality across the WHO MONICA Project populations. Lancet 2000;355:688-700.
(2) Unal B, Critchley JA, Capewell S. Explaining the decline in coronary heart disease mortality in England and Wales between 1981 and 2000. Circulation 2004;109:1101-7.
(3) Wijeysundera HC, Farahati F, Wang X et al. Association of temporal trends in risk factors and treatment uptake with coronary heart disease mortality, 1994-2005. JAMA 2010;303:1841-7.
(4) Tunstall-Pedoe H, Kuulasmaa K, Amouyel P et al. Myocardial infarction and coronary deaths in the World Health Organization MONICA registration project: Registration procedures, event rates and case fatality rates in 30 populations from 21 countries in 4 continents. Circulation 1994;90:583-612.
(5) Norris RM on behalf of the United Kingdom Heart Attack Study Collaborative Group. Fatality outside hospital from acute coronary events in three British Health Districts 1994-95. BMJ 1998;316:1065-70.
(6) The UK Heart Attack Study Collaborative Group. Effect of time from onset to coming under care on fatality of patients with acute myocardial infarction: effect of resuscitation and thrombolytic treatment. Heart 1998;80:114-120.
Robin Norris, retired cardiologist, Auckland, New Zealand (firstname.lastname@example.org)
Liam Penny, cardiologist, University Hospital of Wales, Cardiff, UK . (email@example.com)
Helen Smith (Professor of Primary Care , Brighton and Sussex Medical School, Brighton, UK (H.E.firstname.lastname@example.org)
Competing interests: No competing interests