Heart Failure – A Major Global Health Problem

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Heart Failure – A Major Global Health Problem

Cardiovascular diseases (CVDs) remain the leading cause of morbidity and mortality in developed countries and its burden is progressively increasing.^1–4 Coronary artery disease (CAD) and other conditions, such as hypertensive heart disease or diabetes mellitus, are rated among the foremost reasons for morbi-mortality worldwide.^1–4 In this context, heart failure (HF) has emerged as an extremely important condition that appears to be reaching epidemic proportions. The reported prevalence and incidence of HF varies depending on the studies considered, the definitions used, subjects included in studies and quality of data recorded.^5,6 An overall prevalence of 1–2 % has generally been reported in western countries,^5–7 and this is considerably higher in the elderly i.e. >10 %^.6,8 From the Framingham Heart Study it has been estimated that in the general population the lifetime risk of developing HF at the age of 40 is as high as 20–21 %,⁹ and these figures were reported by the Chicago Heart Association Detection Project in Industry (CHA) and the Cardiovascular Health Study (CHS)¹⁰ to be even higher (20 % to 42 % at age 45, depending on gender and race). Progressively better and more-effective management of HF in the last decades has improved patient survival but its incidence has remained stable;^5,7 hence the burden imposed by HF, as a chronic disease, on both health systems and the individual, has increased, affecting mainly the elderly.^5–7 Despite a reduction in hospitalisation and mortality rates in the past years, these remain high.^5–7,11 Indeed, age- and sex-standardised hospitalisation rates of 468 and 1,359 per 100,000 people for primary and secondary HF, respectively, have been reported in the US in 2009.¹¹ Moreover, in the population-based Rotterdam Study, survival rates after incident HF in subjects ≥55 years old were 86 %, 63 %, 51 % and 35 % at 30 days and 1, 2 and 5 years of follow-up, respectively.⁸ These data underscore the importance of HF as a major global health problem and the need for having reliable and accurate tools that facilitate decisions regarding its prevention, management and outcomes. In this context, the interest in identifying novel biomarkers that can aid diagnosis, risk stratification, prognosis and treatment strategies, has grown considerably in recent years.

Biomarkers in Heart Failure

HF is primarily diagnosed in the presence of symptoms and signs that, in many cases, are non-specific.^7,12 Symptoms of HF result from an impairment in the normal heart function as a consequence of structural or functional disorders affecting ventricular filling and/or blood ejection.^7,12 Recently, biomarkers such as brain natriuretic peptide (BNP) or amino-terminal pro-brain natriuretic peptide (NT-proBNP) have emerged, which appear to represent an important tool for diagnosis, risk stratification and prognosis.^7,12 A biomarker has been defined as “a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention”.¹³ Although this definition is wide and can include any measured parameter, the term ‘biomarker’ is more commonly used in relation to biological substances that are detected in body fluids. Figure 1 summarises the characteristics that make a biomarker useful in clinical practice in the context of CVD and HF.^14–18