Growing Epidemic of Coronary Heart Disease in Low- and Middle-Income Countries

Cardiovascular diseases caused 2.3 million deaths in India in the year 1990; this is projected to double by the year 2020. Hypertension is directly responsible for 57% of all stroke deaths and 24% of all coronary heart disease deaths in India. Indian urban population studies in the mid-1950s used older WHO guidelines for diagnosis (BP > or =160 and/or 95 mmHg) and reported hypertension prevalence of 1.2-4.0%. Subsequent studies report steadily increasing prevalence from 5% in 1960s to 12-15% in 1990s. Hypertension prevalence is lower in the rural Indian population, although there has been a steady increase over time here as well. Recent studies using revised criteria (BP > or =140 and/or 90 mmHg) have shown a high prevalence of hypertension among urban adults: men 30%, women 33% in Jaipur (1995), men 44%, women 45% in Mumbai (1999), men 31%, women 36% in Thiruvananthapuram (2000), 14% in Chennai (2001), and men 36%, women 37% in Jaipur (2002). Among the rural populations, hypertension prevalence is men 24%, women 17% in Rajasthan (1994). Hypertension diagnosed by multiple examinations has been reported in 27% male and 28% female executives in Mumbai (2000) and 4.5% rural subjects in Haryana (1999). There is a strong correlation between changing lifestyle factors and increase in hypertension in India. The nature of genetic contribution and gene-environment interaction in accelerating the hypertension epidemic in India needs more studies. Pooling of epidemiological studies shows that hypertension is present in 25% urban and 10% rural subjects in India. At an underestimate, there are 31.5 million hypertensives in rural and 34 million in urban populations. A total of 70% of these would be Stage I hypertension (systolic BP 140-159 and/or diastolic BP 90-99 mmHg). Recent reports show that borderline hypertension (systolic BP 130-139 and/or diastolic BP 85-89 mmHg) and Stage I hypertension carry a significant cardiovascular risk and there is a need to reduce this blood pressure. Population-based cost-effective hypertension control strategies should be developed.

Trends in hypertension epidemiology in India

Cardiovascular diseases (CVDs) have now become the leading cause of mortality in India. A quarter of all mortality is attributable to CVD. Ischemic heart disease and stroke are the predominant causes and are responsible for >80% of CVD deaths. The Global Burden of Disease study estimate of age-standardized CVD death rate of 272 per 100 000 population in India is higher than the global average of 235 per 100 000 population. Some aspects of the CVD epidemic in India are particular causes of concern, including its accelerated buildup, the early age of disease onset in the population, and the high case fatality rate. In India, the epidemiological transition from predominantly infectious disease conditions to noncommunicable diseases has occurred over a rather brief period of time. Premature mortality in terms of years of life lost because of CVD in India increased by 59%, from 23.2 million (1990) to 37 million (2010). Despite wide heterogeneity in the prevalence of cardiovascular risk factors across different regions, CVD has emerged as the leading cause of death in all parts of India, including poorer states and rural areas. The progression of the epidemic is characterized by the reversal of socioeconomic gradients; tobacco use and low fruit and vegetable intake have become more prevalent among those from lower socioeconomic backgrounds. In addition, individuals from lower socioeconomic backgrounds frequently do not receive optimal therapy, leading to poorer outcomes. Countering the epidemic requires the development of strategies such as the formulation and effective implementation of evidence-based policy, reinforcement of health systems, and emphasis on prevention, early detection, and treatment with the use of both conventional and innovative techniques. Several ongoing community-based studies are testing these strategies.

Cardiovascular Diseases in India Current Epidemiology and Future Directions

Cardiovascular diseases are major causes of mortality and disease in the Indian subcontinent, causing more than 25% of deaths. It has been predicted that these diseases will increase rapidly in India and this country will be host to more than half the cases of heart disease in the world within the next 15 years. Coronary heart disease and stroke have increased in both urban and rural areas. Case-control studies indicate that tobacco use, obesity with high waist:hip ratio, high blood pressure, high LDL cholesterol, low HDL cholesterol, abnormal apolipoprotein A-1:B ratio, diabetes, low consumption of fruits and vegetables, sedentary lifestyles and psychosocial stress are important determinants of cardiovascular diseases in India. These risk factors have increased substantially over the past 50 years and to control further escalation it is important to prevent them. National interventions such as increasing tobacco taxes, labelling unhealthy foods and trans fats, reduction of salt in processed foods and better urban design to promote physical activity may have a wide short-term impact.

https://heart.bmj.com/content/heartjnl/94/1/16.full.pdf

Epidemiology and causation of coronary heart disease and stroke in India

The changing patterns of cardiovascular diseases and their risk factors in the states of India: the Global Burden of Disease Study 1990–2016

Cardiovascular diseases, especially coronary heart disease (CHD), are epidemic in India. The Registrar General of India reported that CHD led to 17% of total deaths and 26% of adult deaths in 2001-2003, which increased to 23% of total and 32% of adult deaths in 2010-2013. The World Health Organization (WHO) and Global Burden of Disease Study also have highlighted increasing trends in years of life lost (YLLs) and disability-adjusted life years (DALYs) from CHD in India. In India, studies have reported increasing CHD prevalence over the last 60 years, from 1% to 9%-10% in urban populations and <1% to 4%-6% in rural populations. Using more stringent criteria (clinical ± Q waves), the prevalence varies from 1%-2% in rural populations and 2%-4% in urban populations. This may be a more realistic prevalence of CHD in India. Case-control studies have reported that important risk factors for CHD in India are dyslipidemias, smoking, diabetes, hypertension, abdominal obesity, psychosocial stress, unhealthy diet, and physical inactivity. Suitable preventive strategies are required to combat this epidemic.

Trends in Coronary Heart Disease Epidemiology in India.

Burden of coronary heart disease in India.

High blood pressure (BP) is a major public health problem in India and its prevalence is rapidly increasing among urban and rural populations. Reducing systolic and diastolic BP can decrease cardiovascular risk and this can be achieved by non-pharmacological (lifestyle measures) as well as pharmacological means. Lifestyle changes should be the initial approach to hypertension management and include dietary interventions (reducing salt, increasing potassium, alcohol avoidance, and multifactorial diet control), weight reduction, tobacco cessation, physical exercise, and stress management. A number of pharmaceutical agents, well evidenced by large randomized clinical trials, are available for initial treatment of high BP. These include older molecules such as thiazide diuretics and beta-blocking agents and newer molecules, dihydropyridine calcium channel blockers (CCB), angiotensin converting enzyme (ACE) inhibitors, and angiotensin receptor blockers (ARB). In view of the recent clinical trials data, some international guidelines suggest that CCB, ACE inhibitors or ARB and not beta-blockers or diuretics should be the initial therapy in hypertension management. Comprehensive hypertension management focuses on reducing overall cardiovascular risk by lifestyle measures, BP lowering and lipid management and should be the preferred initial treatment approach.

Strategies for initial management of hypertension

Coronary heart disease (CHD) is epidemic in India and one of the major causes of disease-burden and deaths. Mortality data from the Registrar General of India shows that cardiovascular diseases are a major cause of death in India now. Studies to determine the precise causes of death in urban Chennai and rural areas of Andhra Pradesh have revealed that cardiovascular diseases cause about 40% of the deaths in urban areas and 30% in rural areas. Analysis of cross-sectional CHD epidemiological studies performed over the past 50 years reveals that this condition is increasing in both urban and rural areas. The adult prevalence has increased in urban areas from about 2% in 1960 to 6.5% in 1970, 7.0% in 1980, 9.7% in 1990 and 10.5% in 2000; while in rural areas, it increased from 2% in 1970, to 2.5% in 1980, 4% in 1990, and 4.5% in 2000. In terms of absolute numbers this translates into 30 million CHD patients in the country. The disease occurs at a much younger age in Indians as compared to those in North America and Western Europe. Rural-urban differences reveal that risk factors like obesity, truncal obesity, hypertension, high cholesterol, low HDL cholesterol and diabetes are more in urban areas. Case-control studies also confirm the importance of these risk factors. The INTERHEART-South Asia study identified that eight established coronary risk factors--abnormal lipids, smoking, hypertension, diabetes, abdominal obesity, psychosocial factors, low fruit and vegetable consumption, and lack of physical activity--accounted for 89% of the cases of acute myocardial infarction in Indians. There is epidemiological evidence that all these risk factors are increasing. Over the past fifty years prevalence of obesity, hypertension, hypercholesterolemia, and diabetes have increased significantly in urban (R2 0.45-0.74) and slowly in rural areas (R2 0.19-0.29). There is an urgent need for development and implementation of suitable primordial, primary, and secondary prevention approaches for control of this epidemic. An urgent and sincere bureaucratic, political, and social will to initiate steps in this direction is required.

Recent trends in coronary heart disease epidemiology in India.

CONTROL? While there are a great many community based models for injury prevention in the scientific literature, the same cannot be said for evidence of their effectiveness. Researchers in Australia performed a comprehensive literature search for formally evaluated community based all cause child injury prevention programmes and succeeded in finding a total of only nine published examples. Only three of those studies found a significant effect of the intervention in question, and the authors suggest that the lack of research suggests ‘‘a clear need to increase effort on developing this evidence base.’’ (Injury Prevention 2004;10:180–5)

Rajeev Gupta

Papers

Trends in Coronary Heart Disease Epidemiology in India.

Burden of coronary heart disease in India.

Strategies for initial management of hypertension

Recent trends in coronary heart disease epidemiology in India.

Coronary heart disease in India.