World Society for Pediatric and Congenital Heart SurgeryThe Challenge of Congenital Heart Disease Worldwide: Epidemiologic and Demographic Facts
Introduction
Congenital heart disease (CHD), the most common congenital birth defect, has long been known as one of the main cause of death in the first year of life. In the last 50 years, the remarkable advances in cardiac surgery have offered real hope of a normal life for many of these children.
It is generally stated that the incidence of CHD (ie, the number of new cases occurring in a defined population during a specified period of time) is 8 per 1,000 live births.1 However, this frequently quoted number is an estimate and is possibly quite inaccurate. Of the approximately 130 million babies born in the world every year, there are more than one million born with CHD. Little is known about the true variation in incidence around the world. Many studies seem to reveal that there could be important geographical variations in the incidence of CHD, as well as of specific heart malformations.
Although there are several CHD and birth defects registries around the world, there have been few comprehensive analyses of the differences between regional incidences worldwide. Additionally, many landmark studies looking at the incidence of CHD were performed before standardization of diagnostic modalities, such as Doppler echocardiography. Therefore, some contradictions are seen between those results and newer studies.
Furthermore, the lack of systematic large studies is compounded by the presence of different definitions of CHD and diagnostic methods. The recent work of the International Society for Nomenclature of Paediatric and Congenital Heart Disease is leading the necessary process for standardization of the diagnostic coding methodology across institutions and geographical borders with the establishment of the International Paediatric and Congenital Cardiac Code.2
It is safe to assume that it is important to study differences in incidence in population groups because those variations can be at the basis for identification of pathogenesis and risk factors, both genetic and environmental. Indeed, even though it is estimated that only 8% to 12% of CHD can be accounted for by environmental factors,3 it still represents a significant burden of disease that could be potentially avoided by controlling the causative agents. Such modifiable risk factors include maternal alcohol consumption, rubella, hydantoin, thalidomide, Accutane, poorly controlled insulin-dependent diabetes, phenylketonuria.3
The challenges of CHD worldwide are numerous. First, there is a need to properly identify the extent of this global health problem by establishing its true incidence. Second, inadequacies with access to diagnosis and uniformity of diagnostic modalities must be resolved. Finally, the care of individuals with CHD is complex and very resource-intensive. Access to care is not equal for all, depending on the countries of origin and regions of the world. Efforts are being made to guarantee some level of care to all children born with CHD, but, needless to say, a tremendous amount of work remains to be done. The recent establishment of the World Society for Pediatric and Congenital Heart Surgery (WSPCHS) will hopefully act as a catalyst for the global improvement of care for children and adults with CHD.
In this article, we will focus on the global challenge of CHD. We will review the literature on the incidence of CHD and, based on this analysis, try to establish regional differences. A careful evaluation of these studies will be done to understand the reason for differences in incidence. From the analysis of the incidence of CHD, we will crudely quantify its global burden. Finally, we will provide some data on the access to care for children and adults with CHD across the world.
Section snippets
Methodology
The first step in identifying and understanding the problem of CHD worldwide is to gather some objective data on the epidemiology and demographic profile of this disease.
Many regional studies have been published to describe the incidence of CHD in specific areas of the world. We conducted a literature search of all articles indexed in PubMed, Embase, and Ovid. The search terms used to conduct this process were combinations of: “congenital”; “heart” or “cardiac”; “disease” or “defect”; and
Incidence of CHD and Geographical Variations
To precisely identify the incidence of CHD, we performed a literature search that yielded 115 studies for analysis. Of those, 35 presented statistics about incidence in the general population. The rest report diagnoses made in patients referred to tertiary care centers, thereby introducing the bias of clinical presentation and access to care (Fig. 1). However, the different study methods have a specific relevance: screening newborns with echocardiography overestimates the number of CHD that
Incidence and Variation of Specific Lesions
The largest number of studies available comment on the overall incidence of CHD and of the three most common defects, VSD, ASD, and TOF (Table 3, Table 4, Table 5;Figure 4, Figure 5). We excluded patent ductus arteriosus from the analysis because its pathologic significance is highly dependent on gestational age. The most common congenital heart lesion in all pediatric populations studied was VSD, with an incidence ranging from 0.3 to 7.7 per 1,000. It represented 30% to 50% of all defects,
Mortality from CHD
It is a known fact that CHD is the most common congenital malformation affecting children. Data on mortality from CHD must be interpreted in the context of the medical and surgical care available in the region studied. Indeed, in regions with little access to cardiac surgery, the mortality data is a reflection of the natural history of the disease. For instance, a study of children referred to cardiologists in Nepal found that of the 89 new patients diagnosed with CHD, 30% had cyanotic heart
Extent of Treatment Around the World and Impact on Outcomes for CHD
It is one thing to know the actual incidence of CHD worldwide and try to establish an idea of the incidence of some specific lesions, but an understanding of the complex challenges posed by CHD would not be complete without having an appreciation of the variations in care provided across the globe. Medical and surgical care of CHD is very resource-intensive. Indeed, it is often complex to make an accurate diagnosis and, to do so, costly diagnostic modalities are required in addition to highly
Conclusion
Congenital heart malformations are the most common of all types of congenital lesions. However, inadequate attention has been given globally to this public health problem over the last decades. Indeed, perhaps appropriately so, health agencies have been more preoccupied with finding solutions to problems such has malnutrition, common infectious agents, and violence against children.
In recent years, possibly because of an increasing global wealth in many countries, and secondary to a better
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