Epidemiology of Cardiovascular Disease¶

Chapter 245 | Part 6: Disorders of the Cardiovascular System · Part 6 – Cardiovascular Disorders · Chapter 245

Key Clinical Points¶

CVD is the leading cause of death globally, accounting for >19 million deaths (33%) in 2022.
The 'epidemiologic transition' describes the shift from infectious diseases/malnutrition to chronic noncommunicable diseases (CVD, cancer) driven by industrialization and lifestyle changes.
LMICs drive global CVD rates; 85% of the world population resides in LMICs, where 15 million CVD deaths occurred in 2019.
CHD and stroke together account for >25% of all deaths worldwide.
Hypertension is a major driver, accounting for 53% of stroke deaths and 53% of CHD deaths.
Diabetes prevalence increased significantly between 1990 and 2017 (129.7% for males; 120.9% for females).
Tobacco use causes ~8.7 million deaths annually (15.4% of all deaths), with 3.2 million being CVD-related.
Secondhand smoke is responsible for 598,000 CVD deaths of non-smokers in 2019.
Age-adjusted CVD mortality has declined by 32.4% (1990–2019), but total deaths increased by 54% due to population growth in LMICs.
Regional variations: Eastern Europe/Central Asia have high rates (~55%); South Asia shows a 50% increase; Japan has lower CHD than stroke rates.
COVID-19 impact: Delayed presentation for ACS or stroke led to worse outcomes.

DEFINITION & OVERVIEW¶

• Current Status: CVD is currently the most common cause of death worldwide. • Historical Context: Before 1900, infectious diseases and malnutrition were primary causes; CVD accounted for <10% of all deaths. • 2022 Data: CVD accounted for over 19 million deaths (33%) globally. • Epidemiologic Transition: ◦ Defined as the transformation in causes of morbidity and mortality during the 20th century driven by industrialization, urbanization, and lifestyle changes. ◦ Impact: Occurs across all races, ethnic groups, and cultures. • Key Clinical Drivers: ◦ Hypertension: Accounts for 53% of stroke deaths and 53% of CHD deaths. ◦ Diabetes: Prevalence increased 129.7% (males) and 120.9% (females) between 1990 and 2017. • COVID-19 Impact: ◦ Patients with acute conditions were hesitant to present to hospitals, leading to delayed presentation for ACS or stroke and worse outcomes.

The Epidemiologic Transition (Table 245-1)¶

• Stage 1: Pestilence and famine ◦ Description: Predominance of malnutrition/infectious diseases; high infant/child mortality; low life expectancy. ◦ CVD Deaths: <10%. ◦ Primary Types: Rheumatic heart disease, cardiomyopathies (infection/malnutrition). • Stage 2: Receding pandemics ◦ Description: Improved nutrition/public health; decline in infectious deaths; precipitous drop in infant mortality. ◦ CVD Deaths: 10–35%. ◦ Primary Types: Rheumatic valvular disease, hypertension, CHD, and stroke (predominantly hemorrhagic). • Stage 3: Degenerate and man-made diseases ◦ Description: Increased fat/caloric intake; decreased physical activity; emergence of hypertension/atherosclerosis; noncommunicable deaths exceed infectious. ◦ CVD Deaths: 35–65%. ◦ Primary Types: CHD and stroke (ischemic and hemorrhagic). • Stage 4: Delayed degenerative diseases ◦ Description: CVD and cancer are primary causes; better treatment/prevention delays events; age-adjusted mortality declines; affects older individuals. ◦ CVD Deaths: 40–50%. ◦ Primary Types: CHD, stroke, and congestive heart failure. • Stage 5: Inactivity and obesity ◦ Description: Rapid increase in overweight/obesity; rise in diabetes/hypertension; low physical activity levels. ◦ CVD Deaths: <40%. ◦ Primary Types: CHD, stroke, congestive heart failure, peripheral vascular disease.

EPIDEMIOLOGY¶

• Global Burden: ◦ CVD accounts for 32% of deaths worldwide. ◦ CHD: 16.2% of all deaths; 10% of global years of life lost (YLLs); 7.2% of disability-adjusted life-years (Daly's). ◦ Stroke: 11.6% of all deaths; 7.5% of YLLs; 5.7% of DALYs. • LMIC Impact: ◦ Burden of stroke is >3x greater in LMICs compared to HICs in terms of DALYs and mortality rates. ◦ 85% of world population lives in LMICs, where 15 million CVD deaths occurred in 2019 (vs. 3.5 million in HICs). • Global Trends (2019 Data): ◦ Total CVD deaths increased by 54% (1990–2019). ◦ Age-adjusted death rates decreased by 32.4% (1990–2019). ◦ Disparity: Age-adjusted rates declined faster in HICs than in middle/lower-income regions. • Regional Variations: ◦ Eastern Europe & Central Asia: Highest CVD death rates (~55%). ◦ South Asia: Experiencing an alarming increase (50% growth) in heart disease. ◦ Japan: Unique dietary patterns keep CHD rates lower than stroke rates. ◦ Southeast/East Asia & Pacific: High prevalence of CVD (40.2% of deaths) in large populations.

Data Methodology (GBD Study)¶

• Refinements: Inclusion of independent estimation of population/fertility; 127 country-years of vital registration. • Reclassifications: Movement of 'misclassified' deaths to dementia, Parkinson's, and atrial fibrillation. • New Additions: Nonrheumatic calcific aortic and degenerative mitral valve disease.

RISK FACTORS¶

• Behavioral Risk Factors: ◦ Tobacco: ◦ >1.3 billion users worldwide. ◦ 8.7 million deaths annually (15.4% of all deaths) → 3.2 million are CVD-related. ◦ Regional usage: HIC (21.6%) ≈ 2x higher than low-income countries (11.2%). ◦ Trends: Reduction in smoking rates across all groups (19%, 12%, and 20% respectively) from 2007–2017. ◦ Future: Expected decline to 16% global average by 2030, but total users may rise due to population growth. ◦ Secondhand Smoke: Responsible for 598,000 CVD deaths of non-smokers in 2019. • Metabolic Risk Factors (GBD 2019 Data): ◦ Lipid levels ◦ Hypertension ◦ Obesity ◦ Diabetes mellitus

MITIGATION STRATEGIES¶

Public Health Measures: ◦ Implement population-wide campaigns against cigarette smoking, unhealthy diets, and physical inactivity.
Targeted Identification: ◦ Identify higher risk subgroups of the population for prioritized intervention.
Clinical Management: ◦ Provide effective treatment and prevention programs to reduce morbidity and mortality.

KEY PEARLS & HIGH-YIELD POINTS¶

• LMIC Dominance: LMICs drive global CVD trends; 15 million deaths in LMICs vs. 3.5 million in HICs (2019). • Age Adjustment Gap: While age-adjusted rates fall globally, the sheer volume of cases in growing/aging LMIs leads to rising absolute death counts. • Stroke Burden: Significant concern in LMICs due to higher mortality and DALY impact compared to HICs. • Regional Trends: Eastern Europe shows high rates (~55%); South Asia shows rapid growth (50%).

Reference Tables¶

TABLE 245-1 Five Stages of the Epidemiologic Transition STAGE Pestilence and famine Predominance of malnutrition and…¶

Harrison's 22e, p.1855

STAGE	DESCRIPTION	DEATHS RELATED TO CVD, %	PREDOMINANT CVD TYPE
Pestilence and famine	Predominance of malnutrition and infectious diseases as causes of death; high rates of infant and child mortality; low mean life expectancy	<10	Rheumatic heart disease, cardiomyopathies caused by infection and malnutrition
	Improvements in nutrition and public health lead to decrease in rates of deaths related to malnutrition and infection; precipitous decline in infant and child mortality rates	10–35
Degenerative and man-made diseases	Increased fat and caloric intake and decrease in physical activity lead to emergence of hypertension and atherosclerosis; with increase in life expectancy, mortality from chronic, noncommunicable diseases exceeds mortality from malnutrition and infectious disease	35–65	CHD and stroke (ischemic and hemorrhagic)
	CVD and cancer are the major causes of morbidity and mortality; better treatment and prevention efforts help avoid deaths among those with disease and delay primary events; age-adjusted CVD morality declines; CVD affecting older and older individuals	40–50
Inactivity and obesity	Overweight and obesity increase at alarming rate; diabetes and hypertension increase; decline in smoking rates levels off; a minority of the population meets physical activity recommendations	<40	CHD, stroke, and congestive heart failure, peripheral vascular disease