How do different definitions of iron deficiency affect its prevalence and prognostic value for 5-year mortality in ambulatory patients with chronic heart failure?
Current guideline criteria for iron deficiency in heart failure may lack prognostic specificity compared to isolated TSAT <20% or serum iron ≤13 μmol/L, which strongly predict 5-year mortality.
Background: Guidelines on heart failure (HF) define iron deficiency (ID) as a serum ferritin 20%. Irrespective of definition, ID was more common in women and those with more severe symptoms, anemia, or preserved ejection fraction. TSAT <20% and serum iron ≤13 μmol/L, but not guideline criteria, were associated with higher 5-year mortality (HR: 1.27; 95% CI: 1.14-1.43; P < 0.001; and HR: 1.37; 95% CI: 1.22-1.54; P < 0.001, respectively). Serum ferritin <100 ng/mL tended to be associated with lower mortality (HR: 0.91; 95% CI: 0.81-1.01; P = 0.09). Conclusions: Different definitions of ID provide discordant results for prevalence and prognosis. Definitions lacking specificity may attenuate the benefits of intravenous iron observed in trials while definitions lacking sensitivity may exclude patients who should receive intravenous iron. Prespecified subgroup analyses of ongoing randomized trials should address this issue.
Masini et al. (2022) studied this question.