S. Capewell1, K. Bennett2, A. Rosengren3, J. Critchley1, L. Palmieri4, S. Giampaoli4
A specialist symposium, entitled ‘Explaining trends in Coronary Heart Disease Mortality: the IMPACT Model’, was presented during the EuroPRevent Congress 2007 and generated great interest.
Coronary heart disease (CHD) remains a leading cause of death and disability in most developed countries including USA. However, CHD mortality rates have deeply decreased since the end of 70s and 80s, with steeper falls in North European countries.
The multinational MONICA study suggested that in countries with falling CHD mortality rates, about one third of the fall was attributable to improved case fatality (mostly treatment related) and two thirds to a reduction in event incidence (mostly attributable to risk factor reductions).
It would be of benefit to determine the components that have resulted in the biggest decreases in mortality, to guide policy in the prevention of CHD, focus health promotion strategies, and target resources towards the most effective interventions in the populations with the greatest need.
Since 1996, Professor Simon Capewell from the University of Liverpool and colleagues have progressively developed and refined a CHD mortality model called IMPACT. This model has been used to explore trends in CHD mortality in contrasting countries, and to comprehensively assess the potential contribution of cardiology treatments and risk factor changes.
The IMPACT CHD model aims to examine the CHD mortality fall in each country in the last 15-20 years, and to determine how much of this fall could be attributed to ‘‘evidence based’’ medical and surgical treatments, and how much to changes in major cardiovascular risk factors. Published trials, meta-analyses, official statistics, longitudinal studies, and surveys were the main data sources.
The model was validated against the actual CHD mortality falls seen in Scotland, England, New Zealand, Finland, and USA before being used to assess substantial mortality increases seen in China. It was then applied in Sweden and Italy. Results using the IMPACT model were generally consistent with other studies using diverse methodologies in different countries including the USA, New Zealand, Finland, and the Netherlands.
Approximately from 50% to 60% of the CHD mortality fall in most European countries and USA between 1980 and 2000 was attributable to reductions in major risk factors; in Finland more than 70%.
These findings emphasise the importance of a comprehensive strategy which actively promotes primary prevention, particularly tobacco control and a healthy diet, and which maximises population coverage of effective treatments.