Abstract and Introduction
In patients with heart failure (HF), iron deficiency (ID) correlates with decreased exercise capacity and poor health-related quality of life, and predicts worse outcomes. Both absolute (depleted iron stores) and functional (where iron is unavailable for dedicated tissues) ID can be easily evaluated in patients with HF using standard laboratory tests (assessment of serum ferritin and transferrin saturation). Intravenous iron therapy in iron-deficient patients with HF and reduced ejection fraction has been shown to alleviate HF symptoms and improve exercise capacity and quality of life. In this paper, we provide information on how to diagnose ID in HF. Further we discuss pros and cons of different iron preparations and discuss the results of major trials implementing iron supplementation in HF patients, in order to provide practical guidance for clinicians on how to manage ID in patients with HF.
Iron deficiency (ID) constitutes the most common form of malnutrition worldwide, affecting more than 2 billion people globally.[1,2] The prevalence of ID in different populations varies according to host factors including age, gender, some physiological, pathological, and environmental factors, and socioeconomic conditions.[2–6] The burden of ID remains significant in both developing and developed countries, for example, in the USA, it affects 2 and 9% of adult males and females, respectively.[7,8]
It needs to be emphasized that ID can occur without decreased haemoglobin. Beyond the traditional view of ID as the cause of anaemia, the spectrum of negative health and economic consequences related to ID is wide, including poor pregnancy outcomes, impaired school performance, and decreased productivity, to name a few. Importantly, although the prevalence of ID is linked with various chronic diseases and conditions, the majority of randomized control trials (RCTs) investigated ID and iron repletion in patients with chronic kidney disease (CKD).[9–11] Nevertheless, in recent years, ID has also been extensively studied in patients with other chronic diseases, such as heart failure (HF).[12,13]
Being involved in cellular metabolism (as a component of respiratory chain proteins in mitochondria and other enzymes crucial for energy generation), iron is indispensable for every living cell.[14,15] Of note, this microelement is particularly important for tissues either with high energy demand (e.g. myocardial tissue, skeletal muscles) or high mitogenic activity (e.g. haematopoietic cells). The presence of ID is also associated with deranged haematopoiesis (erythroid, lymphoid and thrombocyte cell lines).[16–18] Studies, performed in patients with HF, have proven decreased overall exercise capacity and more severe HF symptoms such as fatigue and exertional dyspnoea. Clinical benefits of iron therapy in iron-deficient patients with HF are therefore expected to result not only from the increase in haemoglobin concentration, but also from an improvement in the functioning of non-haematopoietic tissues, such as skeletal muscles.
For metabolic purposes, it is important that we replete iron body stores. The pharmaceutical preparation is important in terms of the amount of iron we are able to successfully deliver to the body, taking into account the safety profile of particular preparations. For therapeutic purposes, iron can be administered through enteral or parenteral routes.
Am J Cardiovasc Drugs. 2017;17(3):183-201. © 2017 Adis Springer International Publishing AG