The effect of postoperative intravenous iron in anaemic, older cardiac surgery patients on disability-free survival (AGE ANEMIA study): study protocol for a multi-centre, double-blind, randomized, placebo-controlled trial

Abstract

Background: Postoperative anaemia is common in older cardiac surgery patients and often caused by iron deficiency. Anaemia may negatively affect recovery after cardiac surgery. This study aims to determine the efficacy of treatment of postoperative iron deficiency anaemia (IDA) with intravenous iron (IVI) on disability 90 days after cardiac surgery in older patients. Methods: This is a randomized placebo-controlled double-blind multi-centre trial. In total, 310 patients aged ≥ 70 years with moderate IDA on postoperative day 1 (haemoglobin 85–110 g/L and ferritin concentration < 100 μg/L or iron saturation < 20%) after uncomplicated elective cardiac surgery (aortic valve repair or coronary artery bypass graft surgery) will be included. Patients will be randomly allocated to receive either IVI (ferric derisomaltose) or placebo (sodium chloride 0.9%) on postoperative day 1 in a 1:1 ratio, stratified by centre and type of cardiac surgery. The primary outcome is disability measured by the 12-item World Health Organization Disability Assessment score 2.0 after 90 days. Secondary outcome measures are the number of postoperative red blood cell (RBC) transfusions, change in reticulocyte haemoglobin content (pg) from randomization to hospital discharge, Hb levels at discharge, hospital complications, dyspnoea (assessed with the Rose Dyspnoea Scale) and health-related quality of life (HRQL) (assessed with The Older Persons and Informal Caregivers-Short Form (TOPICS-SF) questionnaire) after 90 days and days alive and out of hospital after 90 days. Lastly, the functional outcomes (e.g. steep ramp or 6-min walk test) and Hb level after 90 days will be assessed as an exploratory endpoint. Discussion: The results of this study will demonstrate whether early treatment of postoperative IDA with IVI improves disability at 90 days in older cardiac surgery patients. Trial registration: ClinicalTrials.gov NCT04913649. Registered on June 4, 2021.