Heart disease deaths in India: What statistics show

New Delhi: Deaths from heart-related disease among rural Indians have surpassed those among urban Indians, according to a forthcoming study in The Lancet. The study, to be published in the August edition, also suggests that unlike in the West, obesity may not be a big driver of such deaths in India. The study, which provides the first-of-its-kind nationally representative estimates of cardiovascular mortality in India, shows that heart ailments caused more than 2.1 million deaths in India in 2015 at all ages, or more than a quarter of all deaths. At ages 30-69 years, of 1.3 million cardiovascular deaths, 0.9 million (68.4%) were caused by coronary heart disease and 0.4 million (28.0%) by stroke. Adults born after the 1970s are much more vulnerable to such deaths than those born earlier, the study shows.

The study is part of the Million Death Study project set up by the Registrar General of India (RGI) in collaboration with global health experts to investigate the causes of deaths in India using nationally representative survey data.

The study shows that deaths due to coronary heart diseases and strokes were more common among the urban population at the turn of the century. But the trend has reversed since then. Between 2000 and 2015, the age-standardized rate of mortality (per 100,000 person years) due to coronary heart diseases increased among rural men by over 40% even as it declined among urban men. For females, the increase was over 56% in rural India. The study focuses on the 30-69 age groups in both rural and urban India since deaths in this age group are likely to be preventable, and the autopsy data for this age group tends to be more accurate. Mortality rates due to strokes declined in both rural and urban areas, but the slide was steeper in urban India (see Chart 1). While coronary heart disease-related deaths have increased in relatively prosperous states such as Tamil Nadu, Karnataka, Punjab and Haryana, stroke-related deaths have increased in the relatively poorer states of the Northeast, West Bengal, and Chhattisgarh. In the high-burden states of the North-East, West Bengal and Chhattisgarh, stroke mortality rates were about three times higher than the national average.

States with high stroke mortality rates had low mortality rates of coronary or ischaemic heart disease and vice-versa, the study shows. A comparison with 2015-16 data on obesity sourced from the National Family Health Survey (NFHS) shows that there is an inverse relation between obesity and stroke-related deaths across states among both men and women (see Charts 2a and 2b).

The link between body mass index (BMI) and heart-related deaths found in other countries may not apply in the Indian case, the authors of the study argue. “A low BMI might paradoxically predict increased mortality in India for unknown reasons,” the study said. One factor that may explain the twin paradox of higher cardiovascular mortality in rural India and the higher stroke-related mortality in eastern India is access to quality healthcare. Access to doctors and quality hospitals is much lower in rural and poorer parts of the country, where BMI levels also tend to be low. A 2016 WHO report showed that 58% of doctors in urban areas had a medical degree, while only 19% of those in rural areas had such a qualification.

Data from the National Rural Health Mission shows that nearly 8% of primary health centres in rural India were functioning without a doctor, while 61% of them had just one doctor as of March 2017. The Lancet study shows that the proportion of those dying of coronary heart disease with a diagnosis of pre-existing heart disease rose between 2001 and 2013.

At least half of these individuals were taking no regular medication. In high-burden states, the proportion of stroke deaths with a history of pre-existing stroke also saw an increase, and the majority of these individuals were not on any medication. It is likely that the combination of poverty, ignorance and lack of access to sound medical advice is driving heart disease related deaths in the country. The other big driver could be smoking (see Chart 3).

Although the proportion of smokers has come down between 2005-06 and 2015-16, rural India still has a higher share of smokers than urban India. Quitting smoking can help prevent a significant share of premature deaths, the authors of the Lancet study suggest.