A new study involving Oxford Population Health researchers finds that both prevention and improved treatments have helped reduce deaths from heart attacks - but the relative importance of each varies by country, age and sex.
In most developed countries, deaths from heart attacks have reduced significantly since the 1970s, but it has been unclear whether this was mainly due to improved treatments for heart attack patients or preventative measures (for instance, promoting physical activity and targeting risk factors such as high blood pressure, high cholesterol levels and diabetes). Since heart disease remains the world’s largest killer, responsible for 17.9 million deaths each year, understanding what has driven progress so far could help healthcare providers identify the most effective strategies to target next.
To investigate this, Oxford Population Health researchers have contributed to one of the largest international studies of heart attacks to date, covering England, New Zealand, Ontario (Canada) and New South Wales (Australia). The results have been published in The Lancet Public Health.
The researchers used regional administrative hospital records and death registers to identify heart attack events and deaths for the period 1 January 2002 to 31 December, 2015. In total, the study sample included 80.4 million people and 1.95 million heart attacks (almost 581,000 were fatal).
- For all four countries, the overall number of heart attack events and heart attack deaths decreased significantly from 2002 – 2015. Declines in heart attack deaths were between 6.1 and 7.6% per year for each region.
- Both improved treatment and preventative measures had contributed to these trends, however the relative contributions of each varied by location, age and sex.
- In England, for both men and women, declining heart attack death rates were mainly driven by improvements in treatment, while in Canada and New Zealand, prevention had a much bigger effect on falling rates.
- In Australia, treatment improvements contributed to 54% of the reduction in heart attack deaths in men, whereas in women prevention had a bigger effect (60%).
- Among older adults (aged over 55 years), preventative measures appeared to be the main driver of the reduction in heart attack deaths. This indicates that targeted strategies to improve the hospital care of older adults who experience a heart attack could help save even more lives.
- In contrast, for people aged 30–54 years the reductions in deaths were mainly due to more people surviving heart attacks. Preventative measures may therefore be a more effective strategy for this age group.
- For women aged under 55 years in Australia, Canada and England, there was no significant improvement in the prevention of heart attacks over the study period. This is in contrast to all other age groups, and men in the same age group, where the rate of heart attacks fell.
Dr Lucy Wright (Oxford Population Health), study co-lead and lead researcher for England's contribution, said: ‘This is the first study for two decades to investigate whether improvements in prevention or treatment are driving reductions in death rates from heart attacks on an international comparative scale. The results provide insight into further opportunities for reducing the burden of coronary disease, and each country needs to understand its own patterns to know where to target public health and treatment resources.’
Professor Philip Clarke (Oxford Population Health), senior investigator, said: ‘Undertaking analyses on large linked data can provide insights that can help identify gaps in current care that can improve the targeting of future prevention and treatment. This is particularly important with cardiovascular disease as it remains a leading cause of death in the United Kingdom and many other countries.’
The project is a collaboration between the University of Melbourne, University of Otago, University of Oxford, University of Toronto, and University of Western Australia.