Cognitive Function Among Heart Transplant Recipients Before and After Intravenous Iron Supplement for Iron Deficiency: Results From a Randomized, Placebo-Controlled, Double-Blind Treatment Trial.
Bürker, B. S., et al.Clin Transplant. 2025 Nov;39(11):e70370.
Aims
The aim of this study was to examine the effect of intravenous iron supplement on cognitive function of heart transplant recipients with iron deficiency, which was a pre-specified secondary outcome of the IronIC trial.
Interventions
Participants in the IronIC trial were randomly assigned to receive either intravenous iron supplement or placebo.
Participants
94 heart transplat recipients with iron deficiency (aged 18–80 years).
Outcomes
Cognitive function.
Follow-up
6 months
CET Conclusions
This clinical paper represents a study conducted alongside the IronIC study in heart transplant patients. The original study investigated the role of iron supplementation in heart transplant recipients and its impact on iron deficiency. This report uses the same population to analyse the potential impact of this intervention on the cognitive function in heart transplant recipients. The study was randomised, placebo-controlled, and double-blinded. Cognitive function was assessed at baseline and follow up of 6-months. The research team made use of tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB): Reaction Time (RTI), Paired Associates Learning (PAL), and Spatial Working Memory (SWM), capturing these cognitive domains: psychomotor speed, memory, and working memory/executive functions. The mean change in test performance from baseline to 6-month follow-up did not differ significantly between study and placebo group for any of the 6 cognitive measures. The main publication of the IronIC trial showed that intravenous iron supplementation was followed by restoration of iron stores in most of the patients and an increase in mean haemoglobin, but this did not translate to improved cognitive function, as examined in this publication. The exclusion criteria of the study meant that none of the participants had anaemia with haemoglobin <100 g/L, which may have impacted the results. The testing used was purely non-verbal, which may have played a role, along with other very significant comorbidities that also impact very significantly on cognitive decline. The study was a reasonable size, but there was no indication that it was powered adequately for the present outcome.
Trial registration
ClinicalTrials.gov - NCT03662789