Iron deficiency in heart failure with preserved ejection fraction: rationale and design of the FAIR-HFpEF trial

Background: Iron deficiency is highly prevalent in patients with heart failure and has well established diagnostic criteria. Its occurrence is associated with reduced quality of life, exercise capacity and increased hospitalization rates and mortality. The clinical efficacy of treating iron deficiency has not been tested in patients with heart failure with preserved ejection fraction (HFpEF). Methods: The FAIRHFpEF trial aims to enroll patients with HFpEF, reduced exercise capacity and iron deficiency (defined as serum ferritin <100 ng/mL or serum ferritin 100299 ng/mL with transferrin saturation <20%). Patients will be treated in a multicenter, doubleblind, randomized clinical trial with intravenous ferric carboxymaltose (FCM) at doses aimed to replenish iron stores vs. placebo. The primary endpoint is the difference in exercise capacity from baseline to week 24 as assessed by the 6minute walk test. Secondary endpoints include healthrelated quality of life assessments such as the Kansas City Cardiomyopathy Questionnaire, the European Quality of Life5 Dimensions questionnaire and global function tests. Conclusions: The FAIRHFpEF trial is designed to investigate the effect of intravenous iron repletion in iron deficient patients with HFpEF using FCM.