Beyond the Guidelines: The Critical Role of Type 1 Iron Deficiency in Predicting Mortality in Patients with Heart Failure

OBJECTIVE
The criteria for iron deficiency (ID) may encompass depleted iron stores alongside unmet iron demands by cardiomyocytes, potentially serving as predictors of adverse outcomes in patients with heart failure (HF).


METHOD
We included 570 patients with HF. Based on newly proposed definitions of ID, patients were categorized into three groups: Type 1 (transferrin saturation [TSAT] < ≈15-16% with anemia), Type 2 or 3 (TSAT < ≈20% with no or mild anemia) and those meeting HF guideline-defined ID criteria. Binary logistic regression was used to identify independent predictors of one-year all-cause mortality in patients with HF. Cox proportional hazard regression was performed to assess the impact of Type 1 ID on mortality.


RESULTS
Among the 570 HF patients, 175 (30.7%) had Type 1 ID, 250 (43.9%) had Type 2 or 3 ID, and 415 (72.8%) met the guideline-defined criteria for ID. One-year all-cause mortality rates were 38.3% in patients with Type 1 ID, 22.7% in those with Type 2 or 3 ID, and 26.0% in those meeting guideline ID criteria. Increased age (odds ratio [OR]: 1.054, 95% confidence interval [CI]: 1.025-1.084) and Type 1 ID (OR: 1.830, 95% CI: 1.044-3.208) were independent predictors of one-year all-cause mortality. Cox regression analysis demonstrated an increased risk of mortality in HF patients with Type 1 ID compared to those without, in both unadjusted (hazard ratio [HR]: 2.289, 95% CI: 1.644-3.186, P < 0.001) and adjusted (HR: 1.543, 95% CI: 1.070-2.225, P = 0.020) models.


CONCLUSION
Type 1 ID was an independent predictor of one-year all-cause mortality in patients with HF, unlike Type 2 or 3 ID and guideline-defined ID. Patients with Type 1 ID with HF had a higher overall mortality risk compared to those without Type 1 ID.