Cho ME, et al. - In a pre-dialysis chronic kidney disease cohort, researchers examined the link between iron status and mortality. They used data from the Veterans Affairs Corporate Data Warehouse. On the basis of joint quartiles of serum transferrin saturation (percentage) and ferritin concentration (ng/mL), they categorized the cohort into four iron groups: reference (16% to 28%, 55-205 ng/mL), low iron (0.4% to 16%, 0.4-55 ng/mL), high iron (28% to 99.6%, 205-4941 ng/mL), and function iron deficiency (0.8% to 16%, 109-2783 ng/mL). The investigators used matching weights based on multinomial propensity score models as well as Poisson rate-based regression to compare the iron groups for mortality risk. Increased mortality was evident in chronic kidney disease patients in relation to an abnormal iron balance, especially in the presence of functional iron deficiency.