What is the distribution of congenital heart disease frequencies?

Distribution of Congenital Heart Disease Frequencies

Congenital heart disease (CHD) affects approximately 9.1 per 1,000 live births worldwide, with ventricular septal defects being the most common type, accounting for nearly half of all cases. 1

Global Prevalence and Distribution

• The global prevalence of CHD has increased over time from 0.6 per 1,000 live births in the 1930s to 9.1 per 1,000 live births after 1995, representing approximately 1.35 million newborns with CHD annually worldwide. 1

• Significant geographical differences exist in CHD prevalence:

  • Asia reports the highest CHD birth prevalence at 9.3 per 1,000 live births, with relatively more pulmonary outflow obstructions. 1
  • Europe shows a significantly higher CHD birth prevalence (8.2 per 1,000 live births) compared to North America (6.9 per 1,000 live births). 1

• The prevalence of CHD varies by age group, with higher rates observed in younger children (0-4 years), suggesting early mortality in some cases. 2

Distribution by Severity

• When stratified by severity, CHD can be categorized as:

  • Mild/trivial: Most common
  • Moderate: Less common
  • Severe: Least common but most impactful on mortality and morbidity 3

• According to the 32nd Bethesda Conference data, the distribution by severity among adults with CHD is:

  • 45% mild CHD
  • 37% moderate CHD
  • 14% severe CHD 4

Distribution by Specific Defect Types

• The most common CHD types in order of frequency are:

  • Ventricular septal defect (VSD): 46% of all CHD cases 2
  • Atrial septal defect (ASD): 18% 2
  • Patent ductus arteriosus (PDA): 14% 2
  • Tetralogy of Fallot: 10% 2
  • Aortic stenosis: 4% 2
  • Pulmonary stenosis: 4% 2

• Additionally, approximately 20 per 1,000 live births have other common cardiac anomalies such as bicuspid aortic valves, isolated anomalous lobar pulmonary veins, or silent patent ductus arteriosus. 3

Factors Affecting Reported Prevalence

• The reported incidence of CHD varies widely from 4 to 50 per 1,000 live births, primarily due to differences in diagnostic approaches and timing of evaluation. 3

• The increasing prevalence over time reflects improved diagnostic capabilities, particularly the widespread use of echocardiography in neonatal screening, rather than a true increase in incidence. 3

• Access to healthcare and diagnostic facilities significantly impacts reported prevalence, with disparities between high and low-income countries. 1

• The prevalence of CHD is influenced by ethnic and genetic factors, with variations observed across different populations. 4

Clinical Implications

• Nearly 80% of deaths in adult CHD patients are associated with heart failure, sudden death, arrhythmias, and vascular complications. 4

• Hospital admissions occur in 50% of adult CHD patients over a 5-year follow-up period, with 61% of these admissions being for cardiovascular causes. 4

• In the United States, 20% of hospital admissions for adults with CHD are for heart failure, which carries a worse prognosis compared to other reasons for admission. 4

• Dysrhythmias affect up to 50% of patients with adult CHD, including potentially fatal conditions such as sudden death, ventricular tachycardia, and atrial flutter. 4

Population Growth and Future Trends

• The adult CHD population is estimated to increase at approximately 5% annually. 4

• In the United States, there were approximately 850,000 adults with CHD in 2000, with an additional estimated 400,000 increase from 2000 to 2012. 4

• The population of adults with CHD now exceeds the pediatric CHD population for the first time in history, with estimates suggesting the total adult CHD population reached one million by 2005. 4

• The complexity of the adult CHD population is increasing as more patients with severe forms of CHD survive to adulthood due to advances in pediatric cardiac care. 4