AimsUncertainty exists about defining true iron deficiency (ID) in heart failure (HF) patients. We assessed the relationship of different ID definitions with cardiac structure and function, congestion, exercise capacity, and prognosis in HF outpatients.Methods and resultsIron deficiency was defined according to guidelines (G‐ID: ferritin <100 ng/ml or ferritin 100–299 ng/ml with transferrin saturation [TSAT] <20%). Alternative ID definitions based on TSAT (<20%), iron (≤13 μmol/L), and ferritin (<100 or < 300 ng/ml) were explored. Relationships with rest/exercise measures of cardiac function and congestion using ultrasound, effort intolerance and adverse outcome (HF hospitalizations or all‐cause mortality) were assessed. Of 1502 patients (72% with left ventricular ejection fraction [LVEF] ≥50%), 471 (31%) had TSAT <20%, while 728 (48%) had G‐ID. Patients with TSAT <20% or G‐ID had greater left atrial volume but similar LVEF. Lower TSAT, iron and haemoglobin, but not ferritin, were associated with more signs of congestion by ultrasound. After correcting for multiple clinical variables, including haemoglobin, TSAT was directly associated with peak oxygen uptake (standardized coefficient 0.069, p = 0.041), while ferritin was not. There was no interaction with HF phenotype (HF with preserved vs. reduced LVEF). During a median follow‐up of 18 months, TSAT <20% and iron ≤13 μmol/L were associated with worse outcomes in models adjusted for clinical variables, including LVEF and N‐terminal pro‐B‐type natriuretic peptide (hazard ratio 2.48, 95% confidence interval 1.88–3.17 and 1.93, 1.48–2.52, respectively), while G‐ID or ferritin <100 or <300 ng/ml were not.ConclusionIn HF outpatients, TSAT <20% is more consistently associated with congestion by ultrasound and poorer functional capacity than other ID definitions, irrespective of LVEF. TSAT <20% and iron ≤13 μmol/L, but not G‐ID or ferritin‐based ID, predict a worse prognosis in HF outpatients with preserved and reduced LVEF.

中文翻译：

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缺铁与心力衰竭患者的心脏功能、充血、运动能力和预后的关系


目的在心力衰竭 （HF） 患者中定义真正的缺铁 （ID） 存在不确定性。我们评估了不同 ID 定义与 HF 门诊患者心脏结构和功能、充血、运动能力和预后的关系。方法和结果根据指南定义铁缺乏症 （G-ID：铁蛋白 <100 ng/ml 或铁蛋白 100-299 ng/ml 与转铁蛋白饱和度 [TSAT] <20%）。探讨了基于 TSAT （<20%）、铁 （≤13 μmol/L） 和铁蛋白 （<100 或 < 300 ng/ml） 的替代 ID 定义。评估与使用超声测量心脏功能和充血、努力不耐受和不良结果 （HF 住院或全因死亡率） 的休息/运动测量的关系。在 1502 例患者 （72% 的左心室射血分数 [LVEF] ≥50%） 中，471 例 （31%） 为 TSAT <20%，而 728 例 （48%） 为 G-ID。TSAT <20% 或 G-ID 患者的左心房容量更大，但 LVEF 相似。较低的 TSAT、铁和血红蛋白，但不是铁蛋白，与超声充血的更多迹象相关。在校正包括血红蛋白在内的多个临床变量后，TSAT 与峰值摄氧量直接相关 （标准化系数 0.069，p = 0.041），而铁蛋白则不相关。与 HF 表型没有相互作用 （LFEF 保留与降低的 HF）。在中位随访 18 个月期间，TSAT <20% 和铁 ≤13 μmol/L 在根据临床变量调整的模型中与较差的结果相关，包括 LVEF 和 N 末端 B 型利钠肽前体 （风险比分别为 2.48,95% 置信区间 1.88-3.17 和 1.93,1.48-2.52），而 G-ID 或铁蛋白 <100 或 <300 ng/ml 则不是。结论在 HF 门诊患者中，TSAT <20% 与其他 ID 定义相比，与超声充血和功能能力差更一致，与 LVEF 无关。TSAT <20% 和铁 ≤13 μmol/L，但不是 G-ID 或基于铁蛋白的 ID，预示着 LVEF 保留和降低的 HF 门诊患者的预后较差。