Global Trends in Cardiovascular Disease

Within the past 30 years, the global population has seen a dramatic increase in several preventable cardiovascular disease (CVD) risk factors, including hypertension, cholesterol, active and passive exposure to tobacco smoke, physical inactivity, dysglycemia, and overweightedness and obesity. As an example, in Mexico, the prevalence of overweight and obese adults increased more than 3-fold in the span of just 7 years, from 20.2% in 1999 to 69.3% in 2006 [Fernald LC. Soc Sci Med 2007].

Worldwide, these trends reflect a growing burden of CV morbidity and mortality. Indeed, CVD remains the leading cause of death—far outpacing cancer, respiratory disease, and infectious diseases such as HIV/AIDS, tuberculosis, and malaria. Even in developing countries, where the prevalence of infectious disease-related death is high, CVD remains a leading cause of early mortality. K. Srinath Reddy, MD, All India Institute of Medical Sciences, New Delhi, India, described the need to counteract dangerous trends in CV health.

With regard to national interests, premature deaths due to CVD adversely affect the potential for economic growth. For instance, in India, an estimated 17.9 million productive years of life will be lost due to CV deaths among adults aged 35 to 64 years by 2030, accounting for hundreds of billions of dollars in national economic losses. CV deaths in this age group will also claim 10.5 million productive years of life in China and 2.0 million productive years of life in the US by 2030 [Reddy KS. JACC 2007].

CV morbidity also has a devastating economic impact on individual patients and families around the world. In a 2009 study of stroke survivors in China, stroke caused 37% of patients and families to fall below the poverty line [Heeley E et al. Stroke 2009]. In India, 40% of patients with CVD face decreased income, and 13% discontinue treatment due to their inability to pay for health care related costs. As economic data accumulate, it is increasingly clear that the financial devastation that is associated with CVD is a growing public health emergency, Prof. Reddy said.

Addressing the urgent human and financial costs of CVD will require a global movement toward improved disease prevention and treatment. This includes initiatives to strengthen primary care, particularly CV risk factor detection and reduction, as well as early care of acute events. Improving the care of CVD will also require a larger workforce of physician and nonphysician health care professionals. Basic measures to improve diet, increase physical activity, and decrease exposure to environmental pollutants, including tobacco smoke, can dramatically improve global health, Prof. Reddy concluded.

Global Efforts Toward Improved Guideline Adherence

Adherence to clinical guidelines can significantly improve CV outcomes. For instance, in the CRUSADE (Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the ACC/AHA Guidelines) trial, every 10% improvement in guideline adherence was associated with an 11% decrease in inpatient mortality [Peterson ED et al. J Am Coll Cardiol 2004]. However, several potential barriers can limit the successful implementation of clinical guidelines. Sidney C. Smith, MD, University of North Carolina, Chapel Hill, North Carolina, USA, discussed whether clinical guidelines for CVD reduction can be applied to different populations around the world.

Yusuf and colleagues identified several modifiable risk factors that were associated with myocardial infarction (MI) across 52 countries [Yusuf S et al, on behalf of the INTERHEART Study Investigators. Lancet 2004]. Overall, just 9 risk factors accounted for more than 90% of the worldwide burden of MI. Of these, just 2 risk factors—smoking and abnormal apolipoprotein (Apo)-B/ApoA-1 —accounted for two-thirds of global MI risk. Therefore, implementing effective risk reduction strategies that target these risk factors could prevent most cases of premature CVD worldwide.

Although the causes of CVD are common across the world, preventive strategies have traditionally differed between countries for cultural, social, medical, and economic reasons. New global efforts, however, may facilitate a more uniform approach to risk factor reduction. In 2009, the World Heart Federation formed an alliance with the International Diabetes Foundation, the Union for International Cancer Control, and the International Union Against Tuberculosis and Lung Disease to address common risk factors, such as obesity and environmental exposure to tobacco smoke. These new strategies have the potential to improve the implementation of, and adherence to, evidence-based therapies for the prevention and treatment of CVD, Dr. Smith said.

Primary and Secondary Prevention: Can We Afford It?

William Weintraub, MD, Christiana Care Health System, Newark, Delaware, USA, examined the costs that are associated with CV risk reduction, who is responsible for paying these costs, and whether countries can afford more aggressive interventions.

“We are all paying right now with medical care costs, loss of productivity, and early mortality,” Dr. Weintraub said. Therefore, paying for primary prevention of CVD worldwide must become a public health priority, he said.

Therapeutic lifestyle modifications, such as exercise, diet, salt reduction, and tobacco avoidance, are available and affordable everywhere, he said. In addition, most of the basic pharmacological therapies are affordable in most countries in the developing world. The cumulative impact of these therapies can be significant. Treatment with aspirin, beta-blocker therapy, and angiotensin-converting enzyme (ACE) inhibitor therapy can each reduce the 2-year relative risk of CV events by 25%. Lipid-lowering therapies, such as statins, can reduce the risk by 30%. Taken together, aspirin, a beta-blocker, an ACE inhibitor, and a statin can reduce the 2-year relative risk of CV events by 75% [Yusuf S. Lancet 2002].

In a recent World Health Organization survey of developing countries, access and adherence to aspirin therapy for patients with established CVD were high, ranging from 70% to 81%. However, adherence to beta-blocker therapy was poor, ranging from 22% to 48%. Adherence to ACE inhibitors was lower than 40%, and only 14% to 30% of patients were taking statin therapy [Mendis S et al. Bull World Health Organ 2005]. Thus, despite the availability of cost-effective interventions, there are substantial gaps in the prevention of CV events in low-income and middle-income countries.

Improving primary and secondary prevention will require increased access to preventive drug therapy, as well as national drug policies that prioritize CV risk reduction, Dr. Weintraub said. Population-wide educational campaigns to promote healthy lifestyles may also increase awareness of simple and cost-effective approaches for reducing CV risk.

“We need the political will,” Dr. Weintraub said. If the cardiology community is able to implement more aggressive risk-reduction strategies around the world, “there will be tremendous gain in well-being,” he concluded.