MEDICAL MATTERS:'DEATH RATE from heart disease has halved in the last decade," read the headline. It came from a British Medical Journalpaper published a few weeks ago.
Researchers from Oxford University studied 840,175 men and women in England who had suffered from 861,134 heart attacks between 2002 and 2010. Overall, they found death rates for heart attacks fell by 50 per cent in men and 53 per cent in women.
This is a dramatic reduction by any standards. But is it due to a decrease in the occurrence of new heart attacks or the result of improved survival after heart attack? It seems that just over half of the decline in total deaths can be attributed to a fall in the number of new heart attacks, and just under half to a drop in the death rate after heart attack. Some 61 per cent of the people who experienced heart attack were men, 36 per cent of heart attack cases were fatal and 73 per cent of heart attacks occurred in those aged 65 and over. Of 311,419 fatal heart attacks, it is significant that seven out of 10 were sudden deaths that occurred without an admission to hospital.
Because of the scale of the study, and the social similarities between our nations, the results are broadly applicable to the Republic. The substantial drop in the rate of occurrence of heart attacks reflects the impact of both primary and secondary prevention of cardiac risk factors through beneficial changes in the health of the population, while the improvements in death rates following hospital admission are likely to reflect major improvements in medical care.
But what do the results say about the time bomb of obesity we keep hearing about? After all, the research covers a time when obesity rates continued to rise. It seems the drop in heart attacks was least among younger women and younger men, which suggests a possible role for obesity and diabetes that is not being seen in middle-aged people, who enjoyed the greatest reduction in both the number of heart attacks and sudden cardiac death.
Research closer to home suggests we should not underestimate the impact of the smoking ban. Active and passive smoking are known causes of coronary heart disease. In addition, second-hand smoke has been shown to trigger heart attack; therefore the smoking ban would be expected to reduce the number of hospital attendances of people with suspected heart attack.
Dr Edmond Cronin and colleagues from the Coronary Heart Attack Ireland Register in Cork looked at hospital admissions for acute coronary syndromes before and after the introduction of the smoking ban here in 2004. In research recently published in the journal Clinical Cardiology,they say there was a 12 per cent drop in admissions to acute hospitals in the Cork and Kerry region of people with acute coronary conditions such as heart attack and unstable angina in the year after the ban.
Two years later, they found a 13 per cent reduction had occurred, with the biggest drop in men and smokers.
Clearly we need further research in order to understand the contribution of specific elements of prevention and treatment that are responsible for the drop in heart attacks and death rates from heart disease.
Cardiology expert Prof Hugh Tunstall-Pedoe of the University of Dundee notes classic risk factors for heart disease are not the sole determinants of risk. “In prevention, coronary risk is multiplicative, so interventions that affect one or two modifiable risk factors disproportionately benefit overall risk,” he says.
“For example, diet does not operate exclusively through blood cholesterol. Similarly, it is difficult to believe that big reductions in coronary case fatality over decades are determined exclusively by drugs.”
Other questions arise. Are patients now fitter and coronary episodes less severe? Are coronary care units, paramedics and emergency departments more effective than in the past? And, perhaps most urgently, can we do more to prevent sudden death from acute heart attacks?
In other words, will future gains arise because we continue to push or because of a natural fall?