Ferric citrate controls phosphorus and delivers iron in patients on dialysis.

Patients on dialysis require phosphorus binders to prevent hyperphosphatemia and are iron deficient. We studied ferric citrate as a phosphorus binder and iron source. In this sequential, randomized trial, 441 subjects on dialysis were randomized to ferric citrate or active control in a 52-week active control period followed by a 4-week placebo control period, in which subjects on ferric citrate who completed the active control period were rerandomized to ferric citrate or placebo. The primary analysis compared the mean change in phosphorus between ferric citrate and placebo during the placebo control period. A sequential gatekeeping strategy controlled study-wise type 1 error for serum ferritin, transferrin saturation, and intravenous iron and erythropoietin-stimulating agent usage as prespecified secondary outcomes in the active control period. Ferric citrate controlled phosphorus compared with placebo, with a mean treatment difference of -2.2±0.2 mg/dl (mean±SEM) (P<0.001). Active control period phosphorus was similar between ferric citrate and active control, with comparable safety profiles. Subjects on ferric citrate achieved higher mean iron parameters (ferritin=899±488 ng/ml [mean±SD]; transferrin saturation=39%±17%) versus subjects on active control (ferritin=628±367 ng/ml [mean±SD]; transferrin saturation=30%±12%; P<0.001 for both). Subjects on ferric citrate received less intravenous elemental iron (median=12.95 mg/wk ferric citrate; 26.88 mg/wk active control; P<0.001) and less erythropoietin-stimulating agent (median epoetin-equivalent units per week: 5306 units/wk ferric citrate; 6951 units/wk active control; P=0.04). Hemoglobin levels were statistically higher on ferric citrate. Thus, ferric citrate is an efficacious and safe phosphate binder that increases iron stores and reduces intravenous iron and erythropoietin-stimulating agent use while maintaining hemoglobin.

Treatment of nephrogenic systemic fibrosis: limited options but hope for the future.

Nephrogenic systemic fibrosis has now been linked to gadolinium-based contrast exposure in those with compromised kidney function. When present, symptoms can be quite devastating for the patient including severe pain and immobility. Unfortunately there is a lack of a universally effective therapy at this time and the literature, reviewed in this article, is comprised of primarily case reports and small case series allowing few conclusions to be drawn. It is widely recognized that supportive management with physical therapy and aggressive pain management is essential. Resolution of renal function in acute kidney injury appears to attenuate disease in most cases and transplantation has been associated with variable success. Therapies with anecdotal benefit include extracorporeal photopheresis and intravenous sodium thiosulfate. Other interventions have shown limited success. As the mechanism becomes more readily understood, it is hoped that targeted therapy might prove more effective than currently available remedies. In all likelihood prevention will prove to be most effective in avoiding this devastating complication.