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Heart Online First, published on January 30, 2015 as 10.1136/heartjnl-2014-307227 Editorial
Heart failure and iron deficiency anaemia: a complex dance Thomas Callender, Kazem Rahimi Heart failure is a significant public health issue in high income countries and recent evidence suggests that its burden on health services in low and middle-income countries (LMICs) is substantial.1 Heart failure in LMICs is commonly caused by communicable and non-communicable disease, which makes the design and implementation of appropriate responses to this common condition even more challenging than in high income countries. However, data remain sparse, particularly with regards to different heart failure phenotypes and their outcomes in LMICs. Makubi and colleagues2 report on a cohort of 401 consecutive patients with heart failure recruited from outpatient clinics (70%) and inpatient settings at a national referral centre in Dar es Salaam, Tanzania. Although their main objective is to describe the association between anaemia and iron deficiency with future risk of death and hospitalisation, the descriptive aspect of their analyses itself offers several insights into the pattern of heart failure in Tanzania and reveal several important research questions. The first striking findings are the age distribution and the very high prevalence of anaemia. The median age of patients was 56 years (IQR 41–67 years) which is almost two decades younger than patients tend to present in high-income countries. The relative youth of patients with heart failure in sub-Saharan Africa (SSA) is a common finding and it has not been fully explained by the differences in the life expectancy across countries.1 In this context, the observed high prevalence of anaemia (57%) and iron deficiency (49%) are particularly interesting. Anaemia and iron deficiency often accompany chronic heart failure3 and their presence has been associated with worse symptoms and a reduced quality of life.3 In high-income countries, the proportion of patients with heart failure and anaemia is typically between 20% and George Institute for Global Health, University of Oxford, Oxford, UK Correspondence to Professor Kazem Rahimi, George Institute for Global Health, University of Oxford, Oxford Martin School, 34 Broad Street, Oxford OX1 3DB, UK; [email protected]
30%, while the corresponding figure for iron deficiency from a study in a highincome country was 37%.3 As the authors point out, this almost twofold higher prevalence of anaemia may suggest a major underinvestigated factor in the pathophysiology of heart failure in this region, such as malnutrition and chronic infections, and merits further study across the region. The second important observation that the authors make is the relative distribution of underlying aetiologies of heart failure in their patients. In this cohort, 9% of patients had ischaemic heart failure, 35% had heart failure secondary to cardiomyopathies, 44% to hypertension and 12% to rheumatic heart failure.2 From this we know that at least 53% of patients had a non-communicable disease as the underlying determinant of their heart failure. This figure may be even higher, as some of the cardiomyopathies included may have had a noncommunicable cause. This conforms to a previously reported pattern across studies of SSA; a recent meta-analysis put the corresponding figures at 8%, 24% and 45%, respectively, for ischaemic heart disease, cardiomyopathies and hypertension.1 These figures stress the importance of innovative models of care and public health strategies that are better suited to cope with this burden of communicable and non-communicable diseases in resource-poor countries. Finally, the authors investigated the impact of iron deficiency and/or anaemia on a composite outcome of hospitalisation and mortality. They found the presence of iron deficiency anaemia (but not anaemia or iron deficiency on their own) to be associated with a 2.7-fold greater risk of hospitalisation or mortality (HR 2.70 (95% CI 1.42 to 5.14), p
Heart Online First, published on January 30, 2015 as 10.1136/heartjnl-2014-307227 Editorial
Heart failure and iron deficiency anaemia: a complex dance Thomas Callender, Kazem Rahimi Heart failure is a significant public health issue in high income countries and recent evidence suggests that its burden on health services in low and middle-income countries (LMICs) is substantial.1 Heart failure in LMICs is commonly caused by communicable and non-communicable disease, which makes the design and implementation of appropriate responses to this common condition even more challenging than in high income countries. However, data remain sparse, particularly with regards to different heart failure phenotypes and their outcomes in LMICs. Makubi and colleagues2 report on a cohort of 401 consecutive patients with heart failure recruited from outpatient clinics (70%) and inpatient settings at a national referral centre in Dar es Salaam, Tanzania. Although their main objective is to describe the association between anaemia and iron deficiency with future risk of death and hospitalisation, the descriptive aspect of their analyses itself offers several insights into the pattern of heart failure in Tanzania and reveal several important research questions. The first striking findings are the age distribution and the very high prevalence of anaemia. The median age of patients was 56 years (IQR 41–67 years) which is almost two decades younger than patients tend to present in high-income countries. The relative youth of patients with heart failure in sub-Saharan Africa (SSA) is a common finding and it has not been fully explained by the differences in the life expectancy across countries.1 In this context, the observed high prevalence of anaemia (57%) and iron deficiency (49%) are particularly interesting. Anaemia and iron deficiency often accompany chronic heart failure3 and their presence has been associated with worse symptoms and a reduced quality of life.3 In high-income countries, the proportion of patients with heart failure and anaemia is typically between 20% and George Institute for Global Health, University of Oxford, Oxford, UK Correspondence to Professor Kazem Rahimi, George Institute for Global Health, University of Oxford, Oxford Martin School, 34 Broad Street, Oxford OX1 3DB, UK; [email protected]
30%, while the corresponding figure for iron deficiency from a study in a highincome country was 37%.3 As the authors point out, this almost twofold higher prevalence of anaemia may suggest a major underinvestigated factor in the pathophysiology of heart failure in this region, such as malnutrition and chronic infections, and merits further study across the region. The second important observation that the authors make is the relative distribution of underlying aetiologies of heart failure in their patients. In this cohort, 9% of patients had ischaemic heart failure, 35% had heart failure secondary to cardiomyopathies, 44% to hypertension and 12% to rheumatic heart failure.2 From this we know that at least 53% of patients had a non-communicable disease as the underlying determinant of their heart failure. This figure may be even higher, as some of the cardiomyopathies included may have had a noncommunicable cause. This conforms to a previously reported pattern across studies of SSA; a recent meta-analysis put the corresponding figures at 8%, 24% and 45%, respectively, for ischaemic heart disease, cardiomyopathies and hypertension.1 These figures stress the importance of innovative models of care and public health strategies that are better suited to cope with this burden of communicable and non-communicable diseases in resource-poor countries. Finally, the authors investigated the impact of iron deficiency and/or anaemia on a composite outcome of hospitalisation and mortality. They found the presence of iron deficiency anaemia (but not anaemia or iron deficiency on their own) to be associated with a 2.7-fold greater risk of hospitalisation or mortality (HR 2.70 (95% CI 1.42 to 5.14), p
