Iron metabolism biomarkers and mortality risk in U.S. patients with congestive heart failure: NHANES 1999–2018 analysis

Abstract

Background and aimsIron deficiency is a major public health concern. We aimed to assess the predictive capability of 4 iron metabolism biomarkers for all-cause and cardiovascular disease-specific mortality in U.S. patients with congestive heart failure (CHF). Methods and results1904 CHF patients aged ≥20 years were enrolled from NHANES, 1999–2000 to 2017–2018. All analyses were weighted to provide nationally representative estimates. Among 1905 CHF patients, mean age was 71 years, and 1024 (53.8%), 459 (24.1%), 206 (10.8%), and 216 (11.3%) were Non-Hispanic Black, Non-Hispanic White, Hispanic-Mexican American, and Hispanic-Other Hispanic, respectively. During follow-ups, 1080 deaths occurred. Median follow-up time was 5.08 years. Per-unit increase in natural-logarithmic-transformed iron and transferrin saturation decreased all-cause mortality risk separately by 33.0% (adjusted hazard ratio: 0.670, 95% confidence interval: 0.563 to 0.797, P < 0.001) and 32.6% (0.674, 0.495 to 0.917, 0.013), and per-unit increase in transferrin receptor increased mortality risk by 33.7% (1.337, 1.104 to 1.618, 0.004). Two derivates from 3 significant iron biomarkers were generated - transferrin receptor to natural-logarithmic-transformed iron ratio (TRI) and transferrin receptor to natural-logarithmic-transformed transferrin saturation ratio (TRTS), which were significantly associated with all-cause mortality, with per-unit increase corresponding to 2.692- and 1.655-fold increased all-cause mortality risk (P: 0.003 and 0.023). Only iron and TRTS were associated with the significant risk of cardiovascular disease-specific mortality (P: 0.004 and 0.017). ConclusionsOur findings identified 3 iron metabolism biomarkers that were individually, significantly, and independently associated with all-cause mortality in patients with CHF, and importantly 2 derivates generated exhibited stronger predictive capability.