London School of Hygiene & Tropical Medicine

A large international study has found that low-income countries which have people with the lowest risk factors for cardiovascular problems have the highest rates of cardiovascular events and death, while the high-income countries of people with the highest risk factors for heart conditions have a lower rate of severe heart problems and deaths.

The paper, published in the New England Journal of Medicine, involved more than 156,000 people in 17 countries world-wide who took part in the Prospective Urban Rural Epidemiologic (PURE) Study.

Study co-author, Professor Martin McKee from the London School of Hygiene & Tropical Medicine, said: "For the first time ever we have been able to measure the enormous level of unmet need for treatment of heart disease in low and middle income countries. Far too many people are dying unnecessarily for lack of simple treatment, reinforcing the now overwhelming argument for strengthening health systems".

Dr. Salim Yusuf from McMaster University, who was principal investigator for the study, said: "There is a real paradox. We have found that richer countries with higher risk factors have less heart disease and once people have a heart attack or stroke, the risk of dying is substantially less compared to poor countries. But 80% of the deaths each year from cardiovascular disease happen in low and middle income countries."

The authors believe that the difference is down to quality of health care. The study found that health care is as important, if not more important, than avoiding the risk factors in reducing cardiovascular disease.

Dr Yusuf added: "For better heart health, the rich countries should continue to deliver high quality health care while trying to reduce risk factors, while poor countries need to avoid the rise of risk factors but also substantially improve their health care."

Risk factors for cardiovascular problems include smoking, high cholesterol, high blood pressure, diabetes, obesity, stress and not enough fruits and vegetables or exercise.

Study participants were from both urban and rural areas of four low-income countries of Bangladesh, India, Pakistan or Zimbabwe; 10 middle-income countries of Argentina, Brazil, Chile, China, Colombia, Iran, Malaysia, Poland, South Africa and Turkey; and from three high-income countries of Canada, Sweden and the United Arab Emirates.

Funding for the study came from the Population Health Research Institute, many national or local organisations in participating countries as well as the Canadian Institutes of Health Research, the Heart and Stroke Foundation of Ontario and unrestricted grants from several pharmaceutical companies.

The study was led by researchers at the Population Health Research Institute at McMaster University and Hamilton Health Sciences.

Publication:

• S. Yusuf, S. Rangarajan, K. Teo, S. Islam et al. for the PURE Investigators, Cardiovascular Risk and Events in 17 Low-, Middle-, and High-Income Countries, The New England Journal of Medicine. DOI: 10.1056/NEJMoa1311890