Applicability of new proposed criteria for iron deficiency in Japanese patients with heart failure

AIMS: Iron deficiency (ID) is a common co‐morbidity in patients with heart failure (HF). A recent study showed that ID defined by the current guideline criteria was not associated with worse clinical outcomes, and new ID criteria was proposed in patients with HF. However, the external applicability of the new proposed criteria is unclear. We sought to investigate the applicability of the proposed ID criteria in Japanese patients with HF. METHODS AND RESULTS: We prospectively examined 763 patients with chronic HF from a Japanese multicentre registry. The proposed ID criteria were transferrin saturation (TSAT) < 20% and serum iron ≤13 mmol/L and the guideline ID criteria were serum ferritin <100 ng/mL or, when ferritin was 100–299 ng/mL, TSAT <20%. Among all patients (456 male, mean age 71 ± 13 years), 213 (28%) and 444 (58%) met the proposed and guideline ID criteria, respectively. During a median follow‐up period of 436 days (interquartile range 297–565), the primary outcome of all‐cause mortality occurred in 56 (7%) patients. There was no significant difference in the primary outcome between the patients with and without guideline ID criteria (P = 0.32), whereas patients with serum iron ≤10 μmol/L showed higher mortality (P = 0.002). In multivariable Cox regressions, the proposed ID criteria, but not guideline ID criteria, were independently associated with the risk of all‐cause mortality (HR 2.01, 95% CI 1.16–3.51 and HR 1.32, 95% CI 0.76–2.28, respectively), even after adjustment for covariates. CONCLUSIONS: When defined by the proposed criteria and not the guideline criteria, ID was associated with higher mortality in patients with chronic HF, suggesting that the proposed ID criteria is applicable to the Japanese population.