What evidence was found for the comparison of oral iron with placebo?
For the comparison of oral iron with placebo, very low quality evidence was found for the outcomes mortality (n=238, 2 studies), improvement in NYHA class (n=13, study), adverse events (n=225, 1 study) and serious adverse events (n=225, 1 study). The evidence showed a clinically important increase in mortality and clinically important improvement in NHYA class with oral iron (both associated with wide confidence intervals around the effect estimate). Data on improvement in NYHA has only been extracted where quality of life data is not reported in a trial.The evidence for both adverse events and serious adverse events suggested no clinical effect of oral iron. This was also the case for permanent study drug discontinuation which was rated as low quality. The evidence for change in peak VO2, 6 minute walk test distance and KCCQ clinical summary score were reported by the study as median and IQR. Therefore, imprecision could not be assessed.