In recent years, much has been published on the clinical epidemiology of heart failure, including the secular trends in incidence, prevalence, etiology, and prognosis. A clear definition of any condition under study is essential but has proven difficult for heart failure, with no generally accepted gold standard. As a consequence, comparison between studies and countries, over time, is difficult. A full discussion of the diagnostic tests and strategies that can be used in making a diagnosis of heart failure is described in Chap. 28, but an overview of the approaches used in population-based studies is provided here.
Unquestionably, heart failure is an important health care issue. Developed countries spend 1% to 2% of their health care budget on patients with this condition, and heart failure is the single most common diagnostic-related group for admissions to US hospitals. Hospital readmission rates are high, particularly where chronic disease monitoring is poor, and admissions tend to be long, particularly in Europe. Much effort has been expended in improving the standards of care for patients with heart failure, with the publication of international guidelines and the development of chronic disease management programs key to the implementation of these guidelines.
Epidemiologic studies have provided a wealth of information about who is at risk of developing heart failure and how they fare after diagnosis. They also allow predictions to be made about the likely future burden of disease.
Most of the published data have come from studies in developed countries, initially North America, but more recently Europe. Much more limited information is available from the developing world. With epidemiologic transition, it is likely that the epidemiology of heart failure will become increasingly similar across the world, driven by the major etiologic forces of coronary artery disease, hypertension, and diabetes mellitus. Even now, cardiovascular disease is overtaking infectious disease as the leading cause of death worldwide.
Before describing the epidemiology of heart failure, it is important to appreciate the challenge of defining heart failure in a robust but practical manner suitable for population-based studies.
Heart failure is not a complete diagnosis in itself; this requires characterization of the syndrome in terms of its severity, the underlying cardiac abnormality, its etiology, and the manner in which the whole body has adjusted to the pump dysfunction. The advent of high-resolution noninvasive imaging, particularly echocardiography, has helped confirm underlying structural or functional cardiac abnormalities in patients with symptoms and signs suggestive of heart failure. Problems remain in determining what is outside normality, particularly in the aging heart.
The definition of heart failure has evolved over time. There is no currently widely accepted gold standard based on an objective test. Different definitions are used in epidemiologic studies, clinical trials, and clinical practice, making comparisons difficult.1,2 Recent population studies have attempted to apply more clinically based definitions but are labor intensive.
Heart failure has been ...