Beneficial Effects of Long-Term Intravenous Iron Therapy With Ferric Carboxymaltose in Patients With Symptomatic Heart Failure and Iron Deficiency

Study Questions:

What are the benefits and safety of long-term intravenous (i.v.) iron therapy in iron-deficient patients with heart failure (HF)?

Methods:

CONFIRM-HF was a multicenter, double-blind, placebo-controlled trial that enrolled 304 ambulatory symptomatic HF patients with left ventricular ejection fraction ≤45%, elevated natriuretic peptides, and iron deficiency (ferritin <100 ng/ml or 100-300 ng/ml if transferrin saturation <20%). Patients were randomized 1:1 to treatment with i.v. iron, as ferric carboxymaltose (FCM, n = 152) or placebo (saline, n = 152) for 52 weeks. The primary endpoint was the change in 6-minute walk test (6MWT) distance from baseline to week 24. Secondary endpoints included changes in New York Heart Association (NYHA) class; Patient Global Assessment (PGA); 6MWT distance; health-related quality of life (QoL); Fatigue Score at weeks 6, 12, 24, 36, and 52; and the effect of FCM on the rate of hospitalization for worsening HF.

Results:

Treatment with FCM significantly prolonged 6MWT distance at week 24 (difference FCM vs. placebo, 33 ± 11 m; p = 0.002). The treatment effect of FCM was consistent in all subgroups and was sustained to week 52 (difference FCM vs. placebo, 36 ± 11 m; p < 0.001). Throughout the study, an improvement in NYHA class, PGA, QoL, and Fatigue Score in patients treated with FCM was detected, with statistical significance observed from week 24 onward. Treatment with FCM was associated with a significant reduction in the risk of hospitalizations for worsening HF (hazard ratio, 0.39; 95% confidence interval, 0.19-0.82; p = 0.009). The number of deaths (FCM: 12; placebo: 14 deaths) and the incidence of adverse events were comparable between both groups.

Conclusions:

The authors concluded that treatment of symptomatic, iron-deficient HF patients with i.v. iron, as FCM over a 1-year period resulted in sustainable improvement in functional capacity, symptoms, and QoL.

Perspective:

The CONFIRM-HF study shows that the treatment of stable, symptomatic, iron-deficient HF patients with i.v. iron (FCM) results in sustainable improvement in functional capacity, as measured over a 1-year period using the 6MWT. These favorable results were consistent across all prespecified subgroups including patients with and without anemia. The beneficial effects of treatment with FCM were associated with concomitant improvement in patient’s functional status and QoL throughout the study. Importantly, patients treated with FCM demonstrated significantly reduced risk of hospital admission due to worsening HF during 1-year follow-up. Furthermore, long-term correction of iron deficiency with FCM was supported by a good safety profile and was well tolerated. The efficacy of oral iron therapy in iron-deficient HF patients is being tested in a large, prospective, randomized, clinical trial called IRONOUT, and will provide additional insight.

Keywords: Natriuretic Peptides, Ferritins, Follow-Up Studies, Transferrins, Quality of Life, Stroke Volume, Confidence Intervals, Metoprolol, Ferric Compounds, ESC Congress


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