Natural history and prognostic significance of iron deficiency and anaemia in ambulatory patients with chronic heart failure.

Background: Iron deficiency (ID) and anaemia are common in heart failure; less is known about changes over time. Methods: We investigated prevalence, incidence and resolution of ID and anaemia in 906 patients with chronic heart failure (median age 73 (65-79) years, 70% men, 51% HFrEF) one year apart. ID was defined as serum iron ≤13 μmol/L and anaemia as haemoglobin <13.0 g/dL for men or <12.0 g/dL for women. FAIR-HF criteria for ID were also considered. Results: At baseline, 10% had anaemia without ID, 23% had ID without anaemia, 20% had both and 47% had neither. Percentages changed little over one year, but 157 (30%) patients had new-onset ID, 104 (16%) new-onset anaemia, whilst ID resolved in 173 (44%) and anaemia in 63 (23%). Compared to those who remained iron replete (iron >13 μmol/L), mortality was higher in those with persistent or incident ID at 1 year (respectively HR 1.81; [1.23-2.67] and HR 1.40; [0.91-2.14]) in multivariable models (p=0.02). Compared to persistent ID, resolution of ID was associated with a lower mortality (HR 0.61 [0.44-0.86]; p=0.004). Changes in ID defined by FAIR-HF criteria were not similarly associated with mortality. Anaemia was associated with a poor outcome even if it resolved. Conclusions: The prevalence and incidence of ID and anaemia are high in chronic heart failure but so is the rate of resolution. Persistent or incident ID, defined by a serum iron ≤13 μmol/L, is associated with higher mortality and resolution of ID with lower mortality.