Cardiovascular Risk and Events in 17 Low-, Middle-, and High-Income Countries
What are associations between risk-factor burden, incidence of cardiovascular disease, and mortality after a cardiovascular event in low-, middle-, and high-income countries?
PURE (Prospective Urban Rural Epidemiologic) was a prospective cohort study; 156,424 persons from 628 communities in 17 low-, middle-, and high-income countries (spanning five continents) were recruited, starting in January 2003. Risk-factor burden was quantified using the INTERHEART Risk Score (a validated score that includes data on age, gender, smoking status, diabetes, hypertension, family history of heart disease, waist-to-hip ratio, psychosocial factors, diet, and physical activity). Participants were followed for death and incident cardiovascular disease for a median of 4.1 years. Events were adjudicated in each country.
Risk-factor burden was greatest in high-income countries with the mean INTERHEART score highest in these nations, intermediate in middle-income countries, and lowest in low-income countries (p < 0.001). In high-income countries, the INTERHEART score was higher in rural areas, compared to urban areas; in lower- and middle-income countries, the risk score was higher in urban areas, compared to rural areas. Conversely, the rates of major cardiovascular events (death from cardiovascular causes, myocardial infarction, stroke, or heart failure) were lowest in high-income countries, intermediate in middle-income countries, and highest in low-income countries, with rates of 3.99, 5.38, and 6.43 events per 1,000 person-years, respectively (p < 0.001).
While cardiovascular risk as calculated with the INTERHEART Risk Score is the lowest in low-income countries, the rates of major cardiovascular disease and death are conversely and substantially higher in low-income countries, compared to high-income countries.
This is an important study that demonstrates the highest burden of cardiovascular events is in the lowest-income countries, even those countries having the lowest risk-factor profile. Although the data may not be representative of each country, the analysis suggests that risk factors alone cannot account for determining country-level outcomes. Certainly the impact of a high risk factor profile in wealthier countries may be mitigated by better management of risk factors and access to evidence-based therapies.
Keywords: Myocardial Infarction, Waist-Hip Ratio, Stroke, Developed Countries, Heart Failure, Motor Activity, Risk Factors, Diet, Cost of Illness, Hypertension, Smoking, Diabetes Mellitus
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