Hepatic Iron Load at Magnetic Resonance Imaging Is Normal in Most Patients Receiving Peritoneal Dialysis

To the Editor: Over the past 3 decades, the routine use of erythropoeisis-stimulating agents (ESA) has enabled the correction of anemia in most patients with end-stage renal disease (ESRD), reducing the need for blood transfusions and improving the quality of life of severely anemic patients. Almost all ESA-treated hemodialysis patients receive parenteral iron to ensure sufficient available iron for ESA therapy. Iron deficiency is common in hemodialysis patients due to inadequate iron mobilization from repleted storage sites (functional iron deficiency) and blood loss related to the hemodialysis procedure itself, to routine blood sampling for laboratory tests (especially for monitoring of uremia), and to occult fecal bleeding due to uremic enteropathy. Until recently, iron overload was considered to be very rare among hemodialysis patients, but it is now an increasingly recognized clinical problem. The liver is the main site of iron storage, and the liver iron concentration (LIC) correlates closely with total iron stores in patients with genetic hemochromatosis and hemosiderosis secondary to hematological disorders. Magnetic resonance imaging (MRI) is now the gold standard method for LIC estimation in nonrenal patients with iron-overload disorders. A recent study of LIC in hemodialysis patients using quantitative MRI, and another study based on magnetic susceptometry a few years ago, demonstrated a strong link between infused iron dose and liver iron load in this setting. Compared to hemodialysis patients, patients undergoing peritoneal dialysis (PD) have fewer sources of blood loss, and guidelines therefore advocate oral iron as first-line therapy. Furthermore, the ferritin targets recommended in current guidelines are far lower and more physiological in PD than in hemodialysis patients. Thus, almost all hemodialysis patients, but few PD patients, receive parenteral iron. In contrast to the situation regarding hemodialysis patients, there are no published data on liver iron content in PD patients. Moreover, given the major difference in iron therapy between hemodialysis and