Association between iron status markers and kidney outcome in patients with chronic kidney disease

Abstract The associations of iron status markers such as transferrin saturation (TSAT) and serum ferritin with kidney outcome in patients with chronic kidney disease (CKD) were inconsistent and remained strongly debated. Therefore, we aimed to investigate whether TSAT and serum ferritin levels were associated with kidney outcome in such a population. In this prospective study, primary kidney outcome was a composite of doubling of serum creatinine, end-stage kidney disease, or death due to kidney failure. Participants were divided into quartiles (Q1–Q4) according to TSAT or serum ferritin levels. In the multivariable Cox analyses, compared with Q3 of TSAT, the hazard ratios (95% confidence intervals) for Q1, Q2, and Q4 were 1.22 (0.89, 1.69), 1.40 (1.03, 1.89), and 1.15 (0.82, 1.60), respectively. Compared with Q2 of serum ferritin, lower and higher quartiles had a significantly increased risk for kidney outcome; hazard ratios (95% confidence intervals) for Q1, Q3, and Q4 were 1.65 (1.19, 2.29), 1.74 (1.26, 2.40), and 1.53 (1.11, 2.11), respectively. A Fine-Gray model with death before kidney events as a competing risk showed results similar to the above. In CKD, lower and higher ferritin levels were independent risk factors for kidney disease progression.