Health Related Quality of Life in Iron Deficient Heart Transplant Recipients Receiving Intravenous Iron Supplement: A Prespecified Secondary Endpoint in the IronIC Trial

Abstract

<h3>Purpose</h3> Health related quality of life (HRQoL) is reduced in heart transplant (HTx) recipients compared to that of healthy individuals. Intravenous iron supplement improves quality of life in patients with heart failure and iron deficiency (ID). The IronIC trial was designed to test if a single dose of ferric derisomaltose, formerly known as iron isomaltoside, could improve exercise capacity in HTx recipients. HRQoL was a prespecified secondary endpoint. <h3>Methods</h3> In the IronIC trial we randomized 102 HTx recipients with ID to ferric derisomaltose or placebo. ID was defined as ferritin <100μg/l, or ferritin 100-300μg/l in combination with transferrin saturation of <20%. HRQoL was assessed at baseline and at 6 months follow-up using two validated questionnaires: EQ-5D-3L and SF-36v2.The EQ-5D-3L consists of the EQ-Visual Analogue Scale rated from 0-100, and the EQ-5D descriptive system, which we converted to a summary index using a Swedish value set. The SF-36v2 consists of 36 questions, which can be converted to 2 norm-based sum scores: the physical component summary (PCS) and the mental component summary (MCS). A minimal clinically important difference (MCID) was defined as ≥2 for the SF-36 PCS, and ≥3 for the SF-36 MCS. <h3>Results</h3> There was no between-group difference in peak oxygen consumption in the IronIC trial. However, HRQoL was improved in the ferric derisomaltose group compared to controls at follow-up. A significant between group difference was found in the EQ-5D index (Figure 1A), the EQ-5D-VAS (Figure 1B), and the SF-36 MCS (Figure 1C). The SF-36 MCS MCID was also significant. The SF-36 PCS (Figure 1D) and the SF-36 PCS MCID were not significantly different between the groups at follow up. <h3>Conclusion</h3> The prespecified secondary outcome HRQoL was better in the ferric derisomaltose group. These findings suggest a possible approach to improve HRQoL in HTx recipients, and could provide the basis for a trial designed to assess this issue.