Anemia affects one-third of heart failure patients and is associated with increased morbidity and mortality. Despite being one of the commonest comorbidities associated with heart failure, there is a significant knowledge gap about management of anemia in the setting of heart failure due to conflicting evidence from recent trials. The etiology of anemia in heart failure is multifactorial, with absolute and functional iron deficiency, decreased erythropoietin levels and erythropoietin resistance, inflammatory state and heart failure medications being the important causative factors. Anemia adversely affects the already compromised hemodynamics in heart failure, besides being commonly associated with more comorbidities and more severe disease. Though low hemoglobin levels are associated with poor outcomes, the correction of anemia has not been consistently associated with improved outcomes. Parenteral iron improves the functional capacity in iron deficient heart failure patients, the effects are independent of hemoglobin levels, and also the evidence on hard clinical outcomes is yet to be ascertained. Despite all the research, anemia in heart failure remains an enigma. Perhaps, anemia is a marker of severe disease, rather than the cause of poor outcome in these patients. In this review, we discuss the current understanding of anemia in heart failure, its management and the newer therapies being studied.

中文翻译：

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心力衰竭中的贫血：仍然是一个未解之谜

贫血影响三分之一的心力衰竭患者，并与发病率和死亡率增加有关。尽管是与心力衰竭相关的最常见的合并症之一，但由于最近试验的相互矛盾的证据，在心力衰竭的情况下贫血的管理存在重大的知识差距。心力衰竭贫血的病因是多方面的，绝对和功能性铁缺乏、促红细胞生成素水平降低和促红细胞生成素抵抗、炎症状态和心力衰竭药物是重要的致病因素。除了通常与更多的合并症和更严重的疾病相关之外，贫血还会对心力衰竭中已经受损的血流动力学产生不利影响。虽然低血红蛋白水平与不良结果有关，贫血的纠正并不总是与改善的结果相关联。肠外铁剂可改善缺铁性心力衰竭患者的功能能力，其效果与血红蛋白水平无关，而且临床结果的证据尚待确定。尽管进行了所有研究，但心力衰竭中的贫血仍然是一个谜。也许，贫血是严重疾病的标志，而不是这些患者预后不良的原因。在这篇综述中，我们讨论了目前对心力衰竭贫血的理解、其管理和正在研究的新疗法。并且还没有确定关于硬临床结果的证据。尽管进行了所有研究，但心力衰竭中的贫血仍然是一个谜。也许，贫血是严重疾病的标志，而不是这些患者预后不良的原因。在这篇综述中，我们讨论了目前对心力衰竭贫血的理解、其管理和正在研究的新疗法。并且还没有确定关于硬临床结果的证据。尽管进行了所有研究，但心力衰竭中的贫血仍然是一个谜。也许，贫血是严重疾病的标志，而不是这些患者预后不良的原因。在这篇综述中，我们讨论了目前对心力衰竭贫血的理解、其管理和正在研究的新疗法。