Background Phosphate binders are the cornerstone of hyperphosphatemia management in dialysis patients. Ferric citrate is an iron-based oral phosphate binder that effectively lowers serum phosphorus ...levels. Study Design 52-week, open-label, phase 3, randomized, controlled trial for safety-profile assessment. Setting & Participants Maintenance dialysis patients with serum phosphorus levels ≥6.0 mg/dL after washout of prior phosphate binders. Intervention 2:1 randomization to ferric citrate or active control (sevelamer carbonate and/or calcium acetate). Outcomes Changes in mineral bone disease, protein-energy wasting/inflammation, and occurrence of adverse events after 1 year. Measurements Serum calcium, intact parathyroid hormone, phosphorus, aluminum, white blood cell count, percentage of lymphocytes, serum urea nitrogen, and bicarbonate. Results There were 292 participants randomly assigned to ferric citrate, and 149, to active control. Groups were well matched. For mean changes from baseline, phosphorus levels decreased similarly in the ferric citrate and active control groups (−2.04 ± 1.99 SD vs −2.18 ± 2.25 mg/dL, respectively; P = 0.9); serum calcium levels increased similarly in the ferric citrate and active control groups (0.22 ± 0.90 vs 0.31 ± 0.95 mg/dL; P = 0.2). Hypercalcemia occurred in 4 participants receiving calcium acetate. Parathyroid hormone levels decreased similarly in the ferric citrate and active control groups (−167.1 ± 399.8 vs −152.7 ± 392.1 pg/mL; P = 0.8). Serum albumin, bicarbonate, serum urea nitrogen, white blood cell count and percentage of lymphocytes, and aluminum values were similar between ferric citrate and active control. Total and low-density lipoprotein cholesterol levels were lower in participants receiving sevelamer than those receiving ferric citrate and calcium acetate. Fewer participants randomly assigned to ferric citrate had serious adverse events compared with active control. Limitations Open-label study, few peritoneal dialysis patients. Conclusions Ferric citrate was associated with similar phosphorus control compared to active control, with similar effects on markers of bone and mineral metabolism in dialysis patients. There was no evidence of protein-energy wasting/inflammation or aluminum toxicity, and fewer participants randomly assigned to ferric citrate had serious adverse events. Ferric citrate is an effective phosphate binder with a safety profile comparable to sevelamer and calcium acetate.
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.
Background Few studies have examined the association between obesity and markers of kidney injury in a chronic kidney disease population. We hypothesized that obesity is independently associated with ...proteinuria, a marker of chronic kidney disease progression. Study Design Observational cross-sectional analysis. Setting & Participants Post hoc analysis of baseline data for 652 participants in the African American Study of Kidney Disease (AASK). Predictors Obesity, determined using body mass index (BMI). Measurements & Outcomes Urine total protein–creatinine ratio and albumin-creatinine ratio measured in 24-hour urine collections. Results AASK participants had a mean age of 60.2 ± 10.2 years and serum creatinine level of 2.3 ± 1.5 mg/dL; 61.3% were men. Mean BMI was 31.4 ± 7.0 kg/m2 . Approximately 70% of participants had a daily urine total protein excretion rate <300 mg/d. In linear regression analyses adjusted for sex, each 2-kg/m2 increase in BMI was associated with a 6.7% (95% CI, 3.2-10.4) and 9.4% (95% CI, 4.9-14.1) increase in urine total protein–creatinine and urine albumin-creatinine ratios, respectively. In multivariable models adjusting for age, sex, systolic blood pressure, serum glucose level, uric acid level, and creatinine level, each 2-kg/m2 increase in BMI was associated with a 3.5% (95% CI, 0.4-6.7) and 5.6% (95% CI, 1.5-9.9) increase in proteinuria and albuminuria, respectively. The interaction between older age and BMI was statistically significant, indicating that this relationship was driven by younger AASK participants. Limitations May not generalize to other populations; cross-sectional analysis precludes statements regarding causality. Conclusions BMI is associated independently with urine total protein and albumin excretion in African Americans with hypertensive nephrosclerosis, particularly in younger patients.
Background African Americans are at increased risk of kidney failure caused by hypertension. The primary objective of the African American Study of Kidney Disease and Hypertension (AASK) Cohort Study ...is to identify risk factors for progressive kidney disease in African Americans with hypertensive chronic kidney disease in the setting of recommended antihypertensive therapy. Study Design, Setting, & Participants On completion of the AASK Trial, a randomized, double-blind, 3 × 2 factorial trial, participants who had not yet begun dialysis treatment or undergone kidney transplantation were invited to enroll in a prospective Cohort Study. Cohort Study participants received recommended antihypertensive drug therapy, including high rates of angiotensin-converting enzyme–inhibitor (73%) and angiotensin receptor blocker (10%) use with a blood pressure goal of less than 130/80 mm Hg. Predictor, Outcomes, & Measurements Baseline clinical and demographic characteristics are described separately at the baseline of the AASK Trial and Cohort Study. Results Of 1,094 persons enrolled in the AASK Trial (June 1995 to September 2001; mean age, 55 years; 61% men), 691 enrolled in the AASK Cohort Study (April 2002 to present), 299 died or reached dialysis therapy or transplantation, and 104 declined to participate in the AASK Cohort Study. Mean baseline systolic/diastolic blood pressures were 150/96 mm Hg in the Trial and 136/81 mm Hg in the Cohort Study. Cohort Study participants had greater serum creatinine levels at the start of the Cohort Study (2.3 versus 1.8 mg/dL 203 versus 159 μmol/L), corresponding to an estimated glomerular filtration rate of 43.8 versus 50.3 mL/min/1.73 m2 (0.73 versus 0.84 mL/s/1.73 m2 ), than Trial participants and greater urine protein-creatinine ratios (0.38 versus 0.19 mg/mg, respectively). Individuals who were eligible, but declined to participate in the Cohort Study, had greater systolic blood pressure, but similar kidney function. Limitations Some parameters, such as iothalamate glomerular filtration rate, urinary albumin level, echocardiogram, and ambulatory blood pressure, were not performed in both the Trial and the Cohort Study, limiting the ability to evaluate changes in these parameters over time. Conclusion Despite well-controlled blood pressure in the AASK Trial, Cohort Study participants still had evidence of progressive chronic kidney disease. Thus, the AASK Cohort Study is well positioned to address its primary objective.
Background Preclinical data suggest that cyclooxygenase 2 inhibitors decrease proteinuria and preserve glomerular structure in animal models of diabetic nephropathy. The objective of this study is to ...compare the efficacy and safety of celecoxib with placebo for decreasing proteinuria in patients with diabetic nephropathy. Study Design Placebo-controlled double-blinded crossover design. Setting & Participants 24 patients with type 1 or 2 diabetes mellitus, proteinuria with protein of 500 mg/d or greater, and serum creatinine level of 3.0 mg/dL or less. Intervention Patients were randomly assigned to: (1) 6 weeks of celecoxib followed by a 3-week washout period, followed by 6 weeks of placebo followed by another 3-week washout; or (2) 6 weeks of placebo followed by a 3-week washout, followed by 6 weeks of celecoxib followed by another 3-week washout period. All patients were administered quinapril, 20 to 40 mg/d, or irbesartan, 150 to 300 mg/d. All patients were administered aspirin, 81 mg/d. Outcomes & Measurements Proteinuria was assessed by means of protein-creatinine ratio. Data were analyzed using the mixed-effect statistical model. Results There was no significant difference in urinary proteinuria after 6 weeks of treatment with placebo or celecoxib (proteinuria ratio, celecoxib versus placebo, 1.041; 95% confidence interval, 0.846 to 1.282). Celecoxib had no significant effect on potassium or estimated glomerular filtration rate. Frequencies of adverse events were similar between the placebo and celecoxib treatments. Limitations This pilot study was not designed to evaluate the safety or long-term clinical effects of celecoxib. Conclusions Celecoxib, 200 mg/d, for 6 weeks did not alter proteinuria. Few adverse events were noted in this high-risk population.
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