Biomarkers of iron deficiency and prognosis in patients hospitalised with new-onset heart failure and a reduced left ventricular ejection fraction.

Iron deficiency was highly prevalent in patients hospitalised with new-onset HFrEF using current guideline criteria.

• 325 patients were included from 2016-2020 at Sahlgrenska University Hospital
• Median age was 68 (57-76) years and 70.2% were men
• 168 of 325 patients (52%) had iron deficiency using current guideline criteria based on serum ferritin and transferrin saturation (TSAT)
• STFR was available for 224 (69%) of patients

In the prespecified analysis, iron deficiency biomarkers were not statistically significantly associated with the primary composite endpoint of first re-hospitalisation for HF or all-cause mortality after Bonferroni-Holm correction.

• The primary composite event was first re-hospitalisation for HF (HHF) or all-cause mortality
• Median follow-up was 2.2 years
• Bonferroni-Holm correction was applied for multiple testing
• Analyses were adjusted for age, sex, previous HF, left ventricular ejection fraction, HF medications, and comorbidity

Each standard deviation increase in TSAT was associated with a 56% lower risk of re-hospitalisation for HF.

• Hazard ratio for HHF per SD increase in TSAT was 0.44 (95% CI 0.27-0.71)
• This represents a 56% lower risk of HHF per SD increase in TSAT
• This association was identified in the prespecified analysis

Higher iron/STFR and TSAT/STFR ratios were associated with lower risk of re-hospitalisation for HF.

• Each SD increase in iron/STFR ratio was associated with a hazard ratio of 0.58 (95% CI 0.40-0.86) for HHF
• Each SD increase in TSAT/STFR ratio was associated with a hazard ratio of 0.55 (95% CI 0.37-0.83) for HHF
• These associations were identified in the prespecified analysis

In a post hoc sensitivity analysis excluding patients with extreme values, each SD increase in TSAT was associated with a 47% lower risk of the primary composite endpoint.

• Hazard ratio for the primary composite endpoint per SD increase in TSAT was 0.53 (95% CI 0.35-0.79)
• This analysis was post hoc and involved exclusion of patients with extreme values
• This finding was not part of the prespecified analysis plan

The iron/STFR and TSAT/STFR ratios did not appear to offer a substantial prognostic advantage compared with TSAT alone.

• STFR is not currently included in guideline criteria for defining iron deficiency
• Current guidelines define iron deficiency based on serum ferritin and transferrin saturation (TSAT)
• The study investigated whether STFR-based ratios provided additional prognostic value beyond TSAT alone
• The authors concluded that neither ratio appeared to offer a substantial advantage compared with TSAT alone