The Pharmaceutical Journal Vol 264 No 7086 p360
March 4, 2000 Clinical

Evidence-based coronary care linked to decline in heart disease

The reduction in coronary heart disease (CHD) noted in a recent World Health Organisation study is linked to use of new treatments and to changes in CHD-associated risk factors, two papers published this week suggest (Lancet 2000;355:675 and 688). The new papers relate the reduction in cardiovascular events seen in the WHO MONICA project to changes that have occurred in treatments for CHD and in coronary risk factors over the 10 years of the study (from the mid-1980s to the mid-1990s). In MONICA, data were collected from over 100,000 individuals, who came from 38 populations in 21 countries. The treatments studied were aspirin, beta-blockers, angiotensin- converting enzyme inhibitors, coronary artery surgery and thrombolytics. Risk factors analysed were cigarette smoking, blood pressure, blood cholesterol and body weight. Earlier results from the project showed heart disease rates fell in most of the populations studied and there was a clear reduction in cardiovascular deaths.

Reduction in blood pressure contributed to observed decline in heart disease

The MONICA project identified major changes in treatment over the period of the study that strongly related to changes in heart disease rates, the authors say. Populations that introduced proven evidence-based treatments quickly had the greatest improvements whereas those that failed to do so experienced deterioration. The study was unable to specify how much of the decline in coronary events was directly attributable to the adoption of evidence-based coronary care but the researchers conclude that the strong association between them was important.
The lead author of the coronary care paper, Professor Hugh Tunstall-Pedoe (cardiovascular epidemiology unit, University of Dundee) comments: "When the MONICA study was started there was little evidence that treatment had real impact on outcomes in heart disease, but this is no longer true." The most common accompanying trends in risk factors for both sexes were decreasing blood pressure and blood cholesterol and weight increase. The biggest contribution from classic risk factors to the decline in the risk of heart disease seemed to come in men from a reduction in smoking and in women from falling blood pressure.
Commenting on the findings, Dr Kari Kuulasmaa (lead author of the risk factor study and head of the MONICA data centre, Helsinki) says: "The relations between the fall in heart disease rates and changes in risk factors were not as strong as expected from what is known from studies in individuals. Nevertheless the results do endorse prevention campaigns based on changing these modifiable risk factors. They also encourage us to look for other important factors that drive the development of heart disease in the community."
In an accompanying editorial (ibid, p668), Dr Steven Grover (division of clinical epidemiology, Montreal General hospital, Canada) comments that it is reassuring that the "analyses of coronary care suggest that some of the expected benefits associated with evolving clinical care are being realised". Dr Grover adds that the main message of the WHO MONICA project seems to be one of generalisability. He concludes: "Despite incomplete understanding of the causes of cardiovascular disease, some modifiable risk factors that remain important irrespective of the individual's nationality or place of residence have been identified."