This outcome was downgraded for indirectness as the committee agreed that the outcome would give some idea of overall improvement in the severity of HF symptoms. For the important outcomes, the quality of the evidence ranged from high to moderate. The outcome exercise tolerance, as measured by the 6-minute walk test, was rated as moderate quality due to imprecision and haemoglobin change in anaemic patients was rated as high quality. The committee noted that evidence regarding discontinuation and adverse events were graded as low and very low quality, often due to missing data Chronic Heart Failure Treating Heart Failure NICE 2018. All rights reserved. Subject to Notice of rights. ISBN: 978-1-4731-3093-7 and imprecision. However, they were reassured that discontinuation and gastrointestinal disorder rates appeared low. Oral iron versus placebo: For mortality the evidence was rated as very low quality due to risk of bias, imprecision and inconsistency. The committee discussed the inconsistency of the results and noted that the single study showing a negative effect of oral iron was the larger of the 2 studies and weighted more heavily in the meta- analysis. The outcome improvement in NYHA class was also rated as very low quality due to risk of bias, indirectness (as this was interpreted as a surrogate for QoL as it implies an improvement in symptoms) and imprecision. The confidence intervals surrounding the effect estimate were wide which reduced the committee s ability to be confident in the results. The committee noted that evidence regarding discontinuation and adverse events and serious adverse events were graded as low and very low quality, often due to risk of bias and imprecision. 