The high cost of IV iron supplementation and the large population of people with HF requiring treatment would mean a positive recommendation for IV iron supplementation would have a large cost impact for the NHS. Considering this, the committee agreed that overall both the clinical and cost-effectiveness evidence was currently too uncertain to recommend that patients with iron deficiency should be treated with IV iron supplementation. The committee stated that trials currently underway should help to strengthen both the clinical and economic evidence to aid recommendations for IV iron supplementation in the future. Other considerations Iron deficiency is a common comorbidity with HF. It has been estimated that up to 30 to 50% of patients with NYHA class II-IV heart failure have iron deficiency, and that the prognosis for these patients is worse than for patients without iron deficiency. 176 Therefore any recommendations will have implications for a large number of people covered by this guideline. The studies of IV iron included those with and without low haemoglobin and this review did not distinguish between them, as it was the committee s intention to make recommendations that covered both anaemic and non-anaemic patients with iron deficiency. There are guidelines on treating iron deficiency anaemia in the general population, which recommend a trial of oral iron. However, the evidence included within this review does not suggest a clinical benefit of oral iron for people with HFREF and iron deficiency alone. The committee considered a number of points about the potential impacts of making a recommendation for the treatment of iron-deficiency in people with HF. Testing for iron deficiency; treating with oral iron; regimens of IV iron replacement (from provider and patient perspective); and ongoing clinical trials. 