Relationship Between Soluble Transferrin Receptor and Clinical Outcomes in Patients With Heart Failure According to Ejection Fraction Phenotype: The New Zealand PEOPLE Study

•Iron deficiency defined by soluble transferrin receptor criteria is an independent predictor of all-cause mortality and morbidity in patients with heart failure with a preserved ejection fraction.•There is poor concordance between different biomarker definitions of iron deficiency.•Soluble transferrin receptor and transferrin saturation correlate better than ferritin with all-cause mortality in patients with heart failure across the spectrum of ejection fractions. Iron deficiency (ID) is highly prevalent in patients with heart failure (HF) but its impact on prognosis in HF with preserved ejection fraction (HFpEF) remains unclear. We assessed whether ID defined by soluble transferrin receptor (sTfR) criteria is independently associated with all-cause mortality in patients with HFpEF, and evaluated its comparative prognostic performance to ID definitions in common clinical use. Data were analyzed from 788 patients (36% HFpEF) in a prospective multicenter HF cohort study. Baseline plasma samples were analyzed with respect to 4 definitions of ID: sTfR of ≥1.59 mg/L (IDsTfR1), sTfR of ≥1.76 mg/L (IDsTfR2), ferritin of