People living in low-income countries like India, Pakistan, Bangladesh and Zimbabwe have the lowest risk factors for cardiovascular diseases (CVD) compared with those living in high-income countries like Canada, Sweden and the United Arab Emirates. Yet, the rate of deaths from CVD is highest in the low-income countries, not in the high-income countries. The risk factors and the rate of deaths are intermediate in 10 middle-income countries.
However, the incidence of nonmajor cardiovascular events was highest in the high-income countries. The risk factors for cardiovascular problems include smoking, high cholesterol, high blood pressure, diabetes, obesity, stress, insufficient intake of vegetables and fruits and sedentary lifestyle.
Also, people living in rural areas in the low- and middle-income countries have lower risk factors for cardiovascular diseases but higher rate of CVD deaths than their counterparts living in the urban areas. The high-income countries show a completely opposite trend — people in rural areas have higher risk factors than those in the urban areas.
There are two main reasons why the high risk factors for CVD did nottranslate into higher death rates in high-income countries. First, there was better control of risk factors and “frequent use” of proven drugs to reduce the risk of deaths. Second, people living in the high-income countries had greater chances of undergoing interventions like bypass surgery/angioplasty to prevent death.
These were the main findings of the Prospective Urban Rural Epidemiologic (PURE) study involving over 156,000 adults in 17 high, middle, and low-income countries. The number of adults involved in the study in the high, middle, and low-income countries was over 16,000, 105,000 and 35,000 respectively. The results were published last week in The New England Journal of Medicine (NEJM).
Overall, there were 3,900 deaths among the 156,000 participants. After necessary adjustments in the risk score, the rate of deaths per 1,000 person-years of follow-up was lowest (2.19) in the high-income countries, intermediate (5.50) in the middle-income countries and highest (9.84) in the low-income countries. Major cardiovascular events other than deaths too followed the same pattern in the three categories.
What is surprising is that while the mortality rate was nearly the same in rural and the urban areas in the high-income countries, the low-income countries too showed the same trend.
“So the urban areas in India are not doing any better than rural areas,” said Dr. V. Mohan, Director, Madras Diabetes Research Foundation, Chennai. He is one of the authors of the paper.
The conclusion one can draw from the PURE study is that risk factors alone do not determine mortality. Other determinants like easy and timely access to healthcare and medicines, diagnosis of risk factors and treatment/control, and greater awareness play an equally important role in preventing death.
“Everyone thought the prevalence of risk factors has come down in the high-income countries as there are fewer deaths. But this study shows the risk factors have not come down but are tackled better,” Dr. Mohan said. “There, people are quickly taken to hospitals if they have heart attacks.” He also cited the free access to medicines such as statins and aspirins to high risk individuals, smoking cessation programmes, higher intake of fruits and vegetables and exercise as other factors contributing to lower deaths.
“As the risk factors increase in India, the mortality goesup. So the cardiovascular crisis is waiting to worsen unless we improve the healthcare system,” he said. “We must make essential healthcare facilities — diagnosis and essential drugs — available even in PHCs. The secondary level can take care of basic emergency treatment and tertiary level for conducting operations and angioplasty.”
According to Prof. K. Srinath Reddy, President of the Delhi-based Public Health Foundation of India, there are two components — health promotion and healthcare — to reduce risk factors and mortality.
“The health promotion component is to raise awareness and risk reduction and the healthcare component is to provide early detection and effective treatment,” Dr. Reddy said. “In India, both are inefficient.” Prof. Reddy was not involved in the PURE study.
“A large number of people are not even aware of their risk factors, and even if detected, the risk factors are not controlled,” Prof. Reddy said. “It’s a failure of the primary healthcare in India.”