Prevalence and Adverse Outcomes of Iron Deficiency in Heart Failure

Outcomes of iron deficiency (ID) in heart failure (HF) with preserved ejection fraction (HFpEF) or in samples with mixed heart failure subtypes are variably described. Hence, we investigated the prevalence and adverse outcomes of ID in a sample of mixed heart failure subtypes.

Adult patients admitted with HF over a six-month period were retrospectively studied. ID was defined as serum ferritin<100 mcg/L, or serum ferritin 100-300 mcg/L with serum transferrin saturation<20%. For each case of ID, sex- and age-matched (within five years) controls were selected. The primary outcome was the composite of all-cause mortality or readmissions up to 12 months post-index admission.

Of the 245 patients admitted with HF [HFpEF: 83 (70.3%), HFrEF: 35 (29.6%)], 233 met the inclusion criteria. Iron studies were available for 131 patients and 59 (45%) had ID. ID had a significant univariate association with the primary outcome (OR: 3.80, 95% CI: 1.42-10.18, P=0.008), and it remained significant after controlling for age, anaemia, comorbidities, and frailty (OR: 6.04, 95% CI: 1.18-30.85, P=0.031). ID also had a significant independent association with readmissions (OR: 4.61, 95% CI: 1.15-18.43, P=0.03), but not with mortality (OR: 1.17, 95% CI: 0.67-4.35, P=0.257). In post-hoc analysis, ID exhibited a significant association with primary outcome in patients with HFrEF (OR: 14.12, 95% CI: 1.7- 117.33, P=0.014), but not in patients with HFpEF (OR: 1.8, 95% CI: 0.71-4.58, P=0.214).

ID is common in patients hospitalised for heart failure and has been found to have a significant association with the composite primary outcome, largely due to its effect on readmissions. ID may have a differential effect on adverse outcomes with respect to heart failure subtypes.