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.

Dose-response and efficacy of ferric citrate to treat hyperphosphatemia in hemodialysis patients: a short-term randomized trial.

BACKGROUND: Most dialysis patients require phosphate binders to control hyperphosphatemia. Ferric citrate has been tested in phase 2 trials as a phosphate binder. This trial was designed as a dose-response and efficacy trial. STUDY DESIGN: Prospective, phase 3, multicenter, open-label, randomized clinical trial. SETTING & PARTICIPANTS: 151 participants with hyperphosphatemia on maintenance hemodialysis therapy. INTERVENTION: Fixed dose of ferric citrate taken orally as a phosphate binder for up to 28 days (1, 6, or 8 g/d in 51, 52, and 48 participants, respectively). OUTCOMES: Primary outcome is dose-response of ferric citrate on serum phosphorus level; secondary outcomes are safety and tolerability. MEASUREMENTS: Serum chemistry tests including phosphorus, safety data. RESULTS: 151 participants received at least one dose of ferric citrate. Mean baseline phosphorus levels were 7.3 ± 1.7 (SD) mg/dL in the 1-g/d group, 7.6 ± 1.7 mg/dL in the 6-g/d group, and 7.5 ± 1.6 mg/dL in the 8-g/d group. Phosphorus levels decreased in a dose-dependent manner (mean change at end of treatment, -0.1 ± 1.3 mg/dL in the 1-g/d group, -1.9 ± 1.7 mg/dL in the 6-g/d group, and -2.1 ± 2.0 mg/dL in the 8-g/d group). The mean difference in reduction in phosphorus levels between the 6- and 1-g/d groups was 1.3 mg/dL (95% CI, 0.69 to 1.9; P < 0.001), between the 8- and 1-g/d groups was 1.5 mg/dL (95% CI, 0.86 to 2.1; P < 0.001), and between the 8- and 6-g/d groups was 0.21 mg/dL (95% CI, -0.39 to 0.81; P = 0.5). The most common adverse event was stool discoloration. LIMITATIONS: Sample size and duration confirm efficacy, but limit our ability to confirm safety. CONCLUSIONS: Ferric citrate is efficacious as a phosphate binder in a dose-dependent manner. A phase 3 trial is ongoing to confirm safety and efficacy.

The effects of sevelamer and calcium acetate on proxies of atherosclerotic and arteriosclerotic vascular disease in hemodialysis patients.

BACKGROUND: We recently determined that in hemodialysis patients, the use of calcium salts to correct hyperphosphatemia led to progressive coronary artery and aortic calcification as determined by sequential electron beam tomography (EBT) while the use of the non-calcium-containing binder sevelamer did not. Whether the specific calcium preparation (acetate vs. carbonate) might influence the likelihood of progressive calcification was debated. METHODS: To determine whether treatment with calcium acetate was specifically associated with hypercalcemia and progressive vascular calcification, we conducted an analysis restricted to 108 hemodialysis patients randomized to calcium acetate or sevelamer and followed for one year. RESULTS: The reduction in serum phosphorus was roughly equivalent with both agents (calcium acetate -2.5 +/- 1.8 mg/dl vs. sevelamer -2.8 +/- 2.0 mg/dl, p = 0.53). Subjects given calcium acetate were more likely to develop hypercalcemia (defined as an albumin-corrected serum calcium > or =10.5 mg/dl) (36 vs. 13%, p = 0.015). Treatment with calcium acetate (mean 4.6 +/- 2.1 g/day - equivalent to 1.2 +/- 0.5 g of elemental calcium) led to a significant increase in EBT-determined calcification of the coronary arteries (mean change 182 +/- 350, median change +20, p = 0.002) and aorta (mean change 181 +/- 855, median change +73, p < 0.0001). These changes were similar in magnitude to those seen with calcium carbonate. There were no significant changes in calcification among sevelamer-treated subjects. CONCLUSION: Despite purported differences in safety and efficacy relative to calcium carbonate, calcium acetate led to hypercalcemia and progressive vascular calcification in hemodialysis patients.

Hand-assisted laparoscopic radical nephrectomy-associated rhabdomyolysis with ARF.

Intraoperative rhabdomyolysis with resultant acute renal failure is a rare complication seen, most commonly, with urologic surgical procedures. Since the early 1990s, the refinement of laparoscopic techniques has permitted their application more broadly. Among the procedures to benefit from these less invasive surgical methods has been radical nephrectomy. In general, this has resulted in less postoperative pain and shorter convalescence. Nonetheless, laparoscopic radical nephrectomy still represents major surgery and is not free from operative risks. To highlight one of these risks, we present a case of a young, obese man with renal cell carcinoma who underwent a hand-assisted laparoscopic radical nephrectomy that was complicated by rhabdomyolsis resulting in acute renal failure (ARF). We discuss the clinical insults that contributed to the development of azotemia with particular attention paid to our current understanding of the pathogenesis of myoglobinuric ARF. In addition, we review the literature concerning surgery-associated, rhabdomyolytic ARF with the aim of providing clinicians guidance for the avoidance and early recognition of this rare, but very serious, surgical complication.