Soluble transferrin receptor as iron deficiency biomarker: Impact on exercise capacity in heart failure patients

Ras Jiménez, Maria del Mar; Ramos Polo, Raúl; Francesch Manzano, Josep; Corbella Santano, Miriam; Morillas Climent, Herminio; José Bazán, Núria; Jiménez Marrero, Santiago; Garcimartín Cerezo, Paloma; Yun, Sergi; Moliner Borja, Pedro; Torres Cardús, Blanca; Verdú-Rotellar, José María; Díez López, Carles; González-Costello, José; García-Romero, Elena; Frutos Seminario, Fernando de; Triguero Llonch, Laura; Enjuanes Grau, Cristina; Tajes Orduña, Marta; Comín Colet, Josep

doi:http://dx.doi.org/10.3390/jpm13081282

Soluble transferrin receptor as iron deficiency biomarker: Impact on exercise capacity in heart failure patients

Citation

Ras-Jiménez MDM, Ramos-Polo R, Francesch Manzano J, Corbella Santano M, Morillas Climent H, Jose-Bazán N, et al. Soluble transferrin receptor as iron deficiency biomarker: Impact on exercise capacity in heart failure patients. J Pers Med. 2023 Aug 21;13(8):1282. DOI: 10.3390/jpm13081282

Abstract

The soluble transferrin receptor (sTfR) is a marker of tissue iron status, which could indicate an increased iron demand at the tissue level. The impact of sTfR levels on functional capacity and quality of life (QoL) in non-anemic heart failure (HF) patients with otherwise normal systemic iron status has not been evaluated. We conducted an observational, prospective, cohort study of 1236 patients with chronic HF. We selected patients with normal hemoglobin levels and normal systemic iron status. Tissue iron deficiency (ID) was defined as levels of sTfR > 75th percentile (1.63 mg per L). The primary endpoints were the distance walked in the 6 min walking test (6MWT) and the overall summary score (OSS) of the Minnesota Living with Heart Failure Questionnaire (MLHFQ). The final study cohort consisted of 215 patients. Overall QoL was significantly worse (51 ± 27 vs. 39 ± 20, p-value = 0.006, respectively), and the 6 MWT distance was significantly worse in patients with tissue ID when compared to patients without tissue ID (206 ± 179 m vs. 314 ± 155, p-value < 0.0001, respectively). Higher sTfR levels, indicating increased iron demand, were associated with a shorter distance in the 6 MWT (standardized β = -0.249, p < 0.001) and a higher MLHFQ OSS (standardized β = 0.183, p-value = 0.008). In this study, we show that in patients with normal systemic iron parameters, higher levels of sTfR are strongly associated with an impaired submaximal exercise capacity and with worse QoL.