**2. Burden of congenital heart disease in developing countries**

There is a paucity of data on the incidence or birth prevalence of congenital heart disease in most developing countries. A few studies from developing countries coupled with a review of several studies from developed countries suggest similar range from country to country and across different time periods (Subramanyan et al., 2000; Khalil et al., 1994; Hoffman & Kaplan, 2002). However, the reported incidence in developed countries has steadily increased from about 4 to 5 per 1000 live births in the 1950's to as much as 50 to 75 per 1000 live births more recently – largely due to improved diagnosis using echocardiography which enables the diagnosis of many more trivial lesions than had hitherto been the case (Hoffman & Kaplan, 2002). The number of children born with congenital heart disease in developing countries have generally been extrapolated (based on the assumption of similar worldwide incidence) by applying rates obtained from older studies in developed countries to estimated numbers of live births in the developing countries and thus the actual figures may be much higher. Indeed, there generally is a paucity of data on the birth prevalence of all congenital malformations from developing countries, so that the impacts of these defects have been systematically underestimated in the past (Howson et al., 2004). These authors have also emphasized the huge public health importance of these disorders and provided more comprehensive extrapolated data than had hitherto been available. They have further highlighted the role of factors such as constrained diagnostic capabilities, poor healthrelated statistics, lack of birth defect surveillance and registries, and over-reliance on hospital-based rather than population-based studies as factors that have contributed to the underestimation of the toll of congenital anomalies in developing countries, where 94% of birth defects and 95% of their associated deaths occur. Other factors that have contributed both to the higher proportion of birth defects and their absolute numbers in these countries include their higher birth rates and higher prevalence of risk factors such as higher proportion of older mothers, exposure to environmental teratogens and poverty, which is very often associated with maternal malnutrition and more frequent infections. Congenital cardiac malformations constitute at least one quarter of all birth defects and are among the most severe and life-threatening. It is estimated that 960,000 of the slightly over 1 million children born with CHD worldwide annually are born in low and middle income countries – Table 1 (March of Dimes, 2006).

Because of the paucity of treatment facilities in developing regions and the known fact that without treatment 60% of congenital heart diseases are lethal within the first two years of life (Adams, 1959), it is also widely recognized that many more children die from congenital heart disease in developing countries compared with the developed. In addition to the deaths that may be directly attributable to heart disease, many children with congenital heart disease also die from some of the infectious diseases of childhood that are so prevalent in the less developed regions of the world. For these reasons, prevalence studies though more readily available in developing countries than incidence studies, tend to underestimate the burden of congenital heart disease (Saxena, 2005), since prevalence is a function both of incidence and mortality or survival rates. The disability-adjusted life years (DALYs) lost may give a more accurate picture of the disease burden since this measure takes into account the incidence, mortality as well as the quality of life of those who survive. However, there is a paucity of all these categories of data from developing countries, making it difficult to estimate the true burden of congenital heart disease. What is undisputable is that congenital heart disease in developing countries is associated with a very high mortality rate and that in spite of this, hundreds of thousands more children are added every year to the growing pool of affected children requiring intervention. Estimates of the actual numbers of these children however vary widely. This absence of accurate data constitutes one of the major obstacles to efforts to tackle the problem of congenital heart disease in developing countries as it underrates the problem, hinders planning and undermines arguments for more resource allocation in the face of the many other competing health care needs.


*\* Democratic Republic of the Congo* 

264 Congenital Heart Disease – Selected Aspects

of excellence for training and treatment in some developing countries (Stolf 2007, Pezzella 2010). These strategies however are also not without their own inherent challenges. This chapter will highlight some of the peculiarities of management and the practical problems often encountered in the diagnosis, treatment and prevention of congenital heart diseases in

There is a paucity of data on the incidence or birth prevalence of congenital heart disease in most developing countries. A few studies from developing countries coupled with a review of several studies from developed countries suggest similar range from country to country and across different time periods (Subramanyan et al., 2000; Khalil et al., 1994; Hoffman & Kaplan, 2002). However, the reported incidence in developed countries has steadily increased from about 4 to 5 per 1000 live births in the 1950's to as much as 50 to 75 per 1000 live births more recently – largely due to improved diagnosis using echocardiography which enables the diagnosis of many more trivial lesions than had hitherto been the case (Hoffman & Kaplan, 2002). The number of children born with congenital heart disease in developing countries have generally been extrapolated (based on the assumption of similar worldwide incidence) by applying rates obtained from older studies in developed countries to estimated numbers of live births in the developing countries and thus the actual figures may be much higher. Indeed, there generally is a paucity of data on the birth prevalence of all congenital malformations from developing countries, so that the impacts of these defects have been systematically underestimated in the past (Howson et al., 2004). These authors have also emphasized the huge public health importance of these disorders and provided more comprehensive extrapolated data than had hitherto been available. They have further highlighted the role of factors such as constrained diagnostic capabilities, poor healthrelated statistics, lack of birth defect surveillance and registries, and over-reliance on hospital-based rather than population-based studies as factors that have contributed to the underestimation of the toll of congenital anomalies in developing countries, where 94% of birth defects and 95% of their associated deaths occur. Other factors that have contributed both to the higher proportion of birth defects and their absolute numbers in these countries include their higher birth rates and higher prevalence of risk factors such as higher proportion of older mothers, exposure to environmental teratogens and poverty, which is very often associated with maternal malnutrition and more frequent infections. Congenital cardiac malformations constitute at least one quarter of all birth defects and are among the most severe and life-threatening. It is estimated that 960,000 of the slightly over 1 million children born with CHD worldwide annually are born in low and middle income countries

Because of the paucity of treatment facilities in developing regions and the known fact that without treatment 60% of congenital heart diseases are lethal within the first two years of life (Adams, 1959), it is also widely recognized that many more children die from congenital heart disease in developing countries compared with the developed. In addition to the deaths that may be directly attributable to heart disease, many children with congenital heart disease also die from some of the infectious diseases of childhood that are so prevalent in the less developed regions of the world. For these reasons, prevalence studies though more readily available in developing countries than incidence studies, tend to underestimate the burden of congenital heart disease (Saxena, 2005), since prevalence is a function both of incidence and

**2. Burden of congenital heart disease in developing countries** 

the developing world.

– Table 1 (March of Dimes, 2006).

*Adapted from: March of Dimes Global Report on Birth Defects, 2006* 

Table 1. Estimated number of congenital heart disease live births in selected developing countries
