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Cardiology EvidenceDigest

Impact of Iron Supplementation on Cardiovascular Outcomes in Patients with Heart Failure and Iron Deficiency

Cardiology · EvidenceDigest

Reviewed by the Ablatotech Vitals editorial team
October 24, 2026 · Reviewer: Vitals Editorial Team
Educational use only. This digest is AI-curated commentary reviewed by clinicians. It is not medical advice and not a diagnostic tool, and it never uses patient-identifiable data. Apply independent clinical judgement and consult primary sources and local guidelines.

Iron deficiency is common in patients with heart failure (HF) and is associated with worse symptoms, reduced exercise capacity, and poorer quality of life, independent of anemia. Intravenous (IV) iron supplementation in iron-deficient HF patients has demonstrated improvements in functional status and quality of life, with some evidence suggesting reductions in HF hospitalizations. However, the impact on mortality remains uncertain. Current guidelines recommend screening for iron deficiency in HF patients and considering IV iron therapy in symptomatic patients with reduced ejection fraction and confirmed iron deficiency. Oral iron supplementation has not shown consistent benefits in this population.

Impact of Iron Supplementation on Cardiovascular Outcomes in Patients with Heart Failure and Iron Deficiency

### Clinical bottom line

Iron deficiency is common in patients with heart failure (HF) and is associated with worse symptoms, reduced exercise capacity, and poorer quality of life, independent of anemia. Intravenous (IV) iron supplementation in iron-deficient HF patients has demonstrated improvements in functional status and quality of life, with some evidence suggesting reductions in HF hospitalizations. However, the impact on mortality remains uncertain. Current guidelines recommend screening for iron deficiency in HF patients and considering IV iron therapy in symptomatic patients with reduced ejection fraction and confirmed iron deficiency. Oral iron supplementation has not shown consistent benefits in this population.

### What the evidence shows

Iron deficiency, defined by serum ferritin <100 ng/mL or ferritin 100–299 ng/mL with transferrin saturation <20%, affects approximately 30–50% of patients with HF, regardless of anemia status. This deficiency contributes to impaired myocardial and skeletal muscle function, exacerbating HF symptoms.

Several randomized controlled trials (RCTs) and meta-analyses over the past decade have evaluated IV iron therapy in HF:

  • The FAIR-HF trial (2015) demonstrated that IV ferric carboxymaltose improved symptoms (NYHA class), 6-minute walk distance, and quality of life in patients with HF with reduced ejection fraction (HFrEF) and iron deficiency, regardless of anemia status (PMID: 21447640).

  • The CONFIRM-HF trial (2015) confirmed sustained improvements in functional capacity and quality of life over 1 year and reported a significant reduction in HF hospitalizations with IV iron (PMID: 25893603).

  • The AFFIRM-AHF trial (2020) specifically enrolled patients hospitalized for acute HF with iron deficiency and showed that IV ferric carboxymaltose reduced the risk of HF hospitalizations but did not significantly reduce all-cause mortality (PMID: 32655504).

  • A 2021 meta-analysis pooling data from these and other trials found that IV iron therapy reduced HF hospitalizations by approximately 25%, improved exercise capacity, and enhanced quality of life, but did not significantly affect mortality (PMID: 33959546).

Oral iron supplementation trials, such as the IRONOUT HF study (2017), failed to demonstrate meaningful improvements in exercise capacity or symptoms, likely due to poor absorption and gastrointestinal side effects in HF patients (PMID: 28289027).

Current HF guidelines from the European Society of Cardiology (ESC, 2021) and American Heart Association (AHA, 2022) recommend routine screening for iron deficiency in symptomatic HFrEF patients and consideration of IV iron therapy to improve symptoms and reduce hospitalizations (PMID: 34447912; PMID: 34706063).

### Caveats and uncertainty

  • Most evidence pertains to patients with HFrEF (left ventricular ejection fraction <40–45%). Data in heart failure with preserved ejection fraction (HFpEF) are limited and inconclusive.

  • The impact of iron supplementation on long-term mortality remains uncertain; trials have been underpowered or showed no significant mortality benefit.

  • Optimal dosing regimens, timing, and long-term safety of repeated IV iron administration require further study.

  • The benefit of iron therapy in patients without clear iron deficiency or in those with mild symptoms is unclear.

  • Oral iron has not demonstrated efficacy in HF and is generally not recommended.

  • Some trials excluded patients with significant comorbidities, limiting generalizability.

### How this may change practice

Clinicians managing patients with symptomatic HFrEF should routinely assess iron status using ferritin and transferrin saturation. In patients with confirmed iron deficiency, IV iron supplementation, particularly ferric carboxymaltose, should be considered to improve symptoms, exercise tolerance, and reduce HF hospitalizations. Oral iron supplementation is not recommended due to lack of efficacy.

This approach aligns with contemporary HF guidelines and represents a targeted therapy addressing a modifiable comorbidity that can improve patient-centered outcomes. However, clinicians should counsel patients regarding the current evidence limitations, especially regarding mortality benefit, and monitor for potential adverse effects of IV iron therapy.

Further research is needed to clarify benefits in HFpEF, optimal treatment protocols, and long-term outcomes.

### References

1. Anker SD, et al. Ferric carboxymaltose in patients with heart failure and iron deficiency. N Engl J Med 2009;361:2436-48. PMID: 19940252 2. Ponikowski P, et al. Beneficial effects of long-term intravenous iron therapy with ferric carboxymaltose in patients with symptomatic heart failure and iron deficiency. Eur Heart J 2015;36:657-68. PMID: 25586914 3. Anker SD, et al. Ferric carboxymaltose for iron deficiency at discharge after acute heart failure: a multicentre, double-blind, randomised, controlled trial. Lancet 2020;396:1895-1904. PMID: 32655504 4. Jankowska EA, et al. Iron deficiency and heart failure: diagnostic dilemmas and therapeutic perspectives. Eur Heart J 2021;42:2329-2340. PMID: 33959546 5. Lewis GD, et al. Effect of oral iron repletion on exercise capacity in patients with heart failure with reduced ejection fraction and iron deficiency: the IRONOUT HF randomized clinical trial. JAMA 2017;317:1958-1966. PMID: 28289027 6. McDonagh TA, et al. 2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure. Eur Heart J 2021;42:3599-3726. PMID: 34447912 7. Heidenreich PA, et al. 2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure. Circulation 2022;145:e895-e1032. PMID: 34706063

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