What Really Matters

Massive Global Study on Heart Disease Reveals Paradox When Comparing High- to Low-Income Countries

An international study finds the rates of cardiovascular disease and death substantially higher in low-income countries, despite the fact that cardiovascular risk is comparatively lower in these countries. This speaks to the importance of adequate systems for prevention and treatments of various diseases to improve outcomes.

A massive global study with 156,000 participants divided over 17 different countries has provided hard-hitting evidence of the impact of systems of health care on heart disease.

Researchers led by Dr. Salim Yusuf, Director of the Population Health Research Institute (PHRI) of McMaster University and Hamilton Health Sciences, discovered that the rates of major cardiovascular disease (CVD) and death (caused by CVD) were substantially higher in low-income countries, despite the fact that cardiovascular risk is lower in these countries compared to higher-income countries.

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Dr. Salim Yusuf, Director of the Population Health Research Institute and Vice President of Research at Hamilton Health Sciences. Photograph courtesy of McMaster University.

“There is a real paradox. We’ve found that richer countries with higher risk factors have less heart disease. Additionally, once people have a heart attack or stroke, the risk of dying is substantially less compared to poor countries,” explains Yusuf, also Vice President of Research at Hamilton Health Sciences.

This research, which raises key issues that could provide an impetus for establishing better systems for prevention and improved treatment, was published in the prestigious New England Journal of Medicine (NEJM) in August 2014.

Cardiovascular Disease #1 Cause of Death Worldwide

One would be hard pressed to find a disease that is more widespread: CVDs are the number one cause of death globally, according to the World Health Organization (WHO). Roughly 17.3 million people died from CVDs in 2008, representing 30% of all global deaths. Of these deaths, an estimated 7.3 million were due to coronary heart disease and 6.2 million were due to stroke. It is estimated that the number of people who die from CVDs will increase to reach 23.3 million by 2030.

We already know that low- and middle-income countries are disproportionally affected by CVD: Over 80% of CVD deaths take place in low- and middle-income countries, according to WHO.

This WHO research, as well as the new research from Yusuf’s team, makes the connection between health care and health outcomes.

Study Enrolled 156,000+ People from 17 Countries

Returning to the study, the research team led by Yusuf enrolled 156,424 persons from 628 urban and rural communities in 17 countries. Participants came from both urban and rural areas of four low-income countries (Bangladesh, India, Pakistan or Zimbabwe), ten middle-income countries (Argentina, Brazil, Chile, China, Colombia, Iran, Malaysia, Poland, South Africa and Turkey), and three high-income countries (Canada, Sweden and the United Arab Emirates).

The research team assessed the participants’ cardiovascular risk using a validated score for quantifying risk-factor burden without the use of laboratory testing. Higher scores indicated greater risk-factor burden. Participants were followed for approximately four years.


Results Illustrate Paradox

The results of this study reveal a striking paradox: The cardiovascular risk factor levels were highest in high-income countries, intermediate in middle-income countries, and lowest in low-income countries. But the rates of major cardiovascular events (death from cardiovascular causes, myocardial infarction, stroke or heart failure) were lower in high-income countries than in middle- and low-income countries. Fatality rates once an individual suffers a heart attack or a stroke were also lowest in high-income countries.

What was saving the lives and improving the health outcomes of those in higher-income countries? Better health services, better control of risk factors, and more frequent use of proven pharmacologic therapies and revascularization procedures, the researchers conclude. With this new knowledge gained from Yusuf’s team, things may change in terms of prevention and treatment.

Funding for this study came from PHRI, the national or local organizations in participating countries, the Canadian Institutes of Health Research, the Heart and Stroke Foundation of Ontario and unrestricted grants from several pharmaceutical companies.

To read the article in the NEJM, go here: http://bit.ly/1mUU3TF.