The effects of intravenous iron on mobility in older adults following hip fracture surgery: protocol for a multicentre, parallel group, randomised controlled trial - the IronHip trial.

introductionHalf of all patients with a hip fracture (HF) do not recover their pre-fracture mobility after 1 year. Mobility and functional capabilities may be impaired by postoperative low haemoglobin levels and iron deficiency. The primary objective of this trial is to compare the effect of a single postoperative dose of ferric derisomaltose 20 mg/kg body weight relative to placebo on the recovery of functional mobility in patients. METHODS AND ANALYSIS: The IronHip trial is a multicentre, randomised, double-blind, placebo-controlled trial with participants allocated in a 1:1 ratio to receive intravenous iron or placebo. The eligible population is participants aged 65 years or older who have undergone HF surgery and have a haemoglobin concentration below 105 g/L measured between postoperative day 1 and 5. In total, 210 participants will be randomised. Main analyses will be conducted in the intention-to-treat population using a mixed model for repeated measures, including assessments at baseline and at 4, 6 and 12 weeks after randomisation. Treatment effects will be estimated from the treatment-by-time interaction and reported as between-group differences in least-squares mean New Mobility Score with 95% CIs. The secondary outcomes are haemoglobin, red blood cell transfusions, fatigue, quality of life, self-rated health, fear of falls, 30 s sit-to-stand test, activities of daily living, pain, days alive and at home up to 30 days, mortality and serious adverse events. Exploratory outcomes are cost-effectiveness, physical activity, hand grip strength, knee extension strength, cognition, ferritin and transferrin saturation. Recruitment was initiated on 9 June 2025. ETHICS AND DISSEMINATION: The IronHip trial has been approved by the Danish Medicines Agency and the Danish Medical Research Ethics Committee. The protocol follows the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) guidelines, the Declaration of Helsinki and the Good Clinical Practice guidelines. The trial findings will be reported according to the Consolidated Standards of Reporting Trials (CONSORT) statement in peer-reviewed journals. REGISTRATION DETAILS: EU CT number: 2024-5 15 116-42-00, authorised 9 February 2025. CLINICALTRIALS: gov: NCT06898814.