Background
Phase 3, double-blind, placebo-controlled RCT (AFFIRM-AHF). 1,108 patients with acute decompensated heart failure and iron deficiency (ferritin <100 ng/mL or ferritin 100–299 ng/mL with TSAT <20%), stabilized before discharge. Randomized to IV ferric carboxymaltose (FCM) or placebo initiated before or shortly after discharge. Rationale: post-hospitalization HF patients are at highest risk for readmission; iron deficiency is a modifiable target. Building on FAIR-HF (outpatient, stable HF), AFFIRM-AHF tested acute HF + iron deficiency targeting hospitalization prevention.
Interventions and follow up
Arm A: IV ferric carboxymaltose up to 3 doses based on iron deficit (weeks 0, 6, 12 — inpatient first dose if tolerated), then maintenance at weeks 24 and 36 if iron-deficient
Arm B: IV saline placebo at the same timepoint
Primary endpoint: Composite of first HF hospitalization or cardiovascular death through 52 week
mFollow up: 52 week
Arm B: IV saline placebo at the same timepoint
Primary endpoint: Composite of first HF hospitalization or cardiovascular death through 52 week
mFollow up: 52 week
Results
Primary composite (HF hospitalization or CV death): Rate ratio 0.79, 95% CI 0.62–1.01 — P=.059 (missed pre-specified significance threshold of P<.05)
Total HF hospitalizations: Rate ratio 0.74, 95% CI 0.58–0.94 — P=.013
CV death: HR 0.96, 95% CI 0.72–1.28 (not significant)
HF hospitalization + CV death (sensitivity): Significant reduction in total events (P<.05) by several prespecified recurrent event analyses
Total HF hospitalizations: Rate ratio 0.74, 95% CI 0.58–0.94 — P=.013
CV death: HR 0.96, 95% CI 0.72–1.28 (not significant)
HF hospitalization + CV death (sensitivity): Significant reduction in total events (P<.05) by several prespecified recurrent event analyses
Adverse events
Main adverse events: Similar safety profile to placebo. Hypophosphatemia grade ≥3 in ~2% of FCM arm. No significant difference in serious AEs. Day-90 hospitalization rates favored FCM numerically across multiple analyses. Trial stopped early due to COVID-19 (9% missing primary endpoint data) — this affected power.
Conclusions
FCM narrowly missed the primary endpoint composite (P=.059) but significantly reduced total HF hospitalizations (P=.013), with COVID-19-related early stopping reducing statistical power — trial directionally positive and clinically impactful for reducing recurrent HF events.
Key Limitations
Key Limitations: COVID-19 pandemic caused early trial stoppage, reducing power by ~10% — trial was designed for 1,320 events but only 1,196 were accrued. The primary endpoint P=.059 narrowly misses significance; total HF hospitalizations was significant (P=.013). No mortality benefit. The pre-specified primary composite weighting of CV death equally with first HF event may have diluted the signal from HF hospitalization prevention. Predominantly HFrEF/HFmrEF — HFpEF patients underrepresented.
Clinical Context
AFFIRM-AHF, despite narrowly missing P<.05, is broadly interpreted as supporting IV iron for iron-deficient acute HF patients given significant reduction in total HF hospitalizations and the COVID truncation caveat. Combined with FAIR-HF, CONFIRM-HF (stable HF), and IRONMAN (ferric derisomaltose HF), IV iron is guideline-recommended for iron-deficient HFrEF. Current ESC 2021 HF guidelines: Class IIa recommendation for FCM to reduce HF hospitalizations in symptomatic, iron-deficient HFrEF with LVEF <45%.
References