Health care providers' support of patients' autonomy, phosphate medication adherence, race and gender in end stage renal disease.

This study was designed to assess dialysis subjects' perceived autonomy support association with phosphate binder medication adherence, race and gender. A multi-site cross-sectional study was conducted among 377 dialysis subjects. The Health Care Climate (HCC) Questionnaire assessed subjects' perception of their providers' autonomy support for phosphate binder use, and adherence was assessed by the self-reported Morisky Medication Adherence Scale. Serum phosphorus was obtained from the medical record. Regression models were used to examine independent factors of medication adherence, serum phosphorus, and differences by race and gender. Non-white HCC scores were consistently lower compared with white subjects' scores. No differences were observed by gender. Reported phosphate binder adherence was associated with HCC score, and also with phosphorus control. No significant association was found between HCC score and serum phosphorus. Autonomy support, especially in non-white end stage renal disease subjects, may be an appropriate target for culturally informed strategies to optimize mineral bone health.

Self-Motivation Is Associated With Phosphorus Control in End-Stage Renal Disease.

OBJECTIVE: Hyperphosphatemia is common in end-stage renal disease and associates with mortality. Phosphate binders reduce serum phosphorus levels; however, adherence is often poor. This pilot study aims to assess patients' self-motivation to adhere to phosphate binders, its association with phosphorus control, and potential differences by race. DESIGN AND METHODS: Cross sectional design. Subjects were enrolled from one academic medical center dialysis practice from July to November 2012. Self-motivation to adhere to phosphate binders was assessed with the autonomous regulation (AR) scale (range: 1-7) and self-reported medication adherence with the Morisky Medication Adherence Scale. Linear regression models adjusting for age, sex, health literacy, and medication adherence were applied to determine associations with serum phosphorus level, including any evidence of interaction by race. RESULTS: Among 100 participants, mean age was 51 years (±15 years), 53% were male, 72% were non-white, 89% received hemodialysis, and mean serum phosphorus level was 5.7 ± 1.6 mg/dL. More than half (57%) reported the maximum AR score (7). Higher AR scores were noted in those reporting better health overall (P = .001) and those with higher health literacy (P = .01). AR score correlated with better medication adherence (r = 0.22; P = .02), and medication adherence was negatively associated with serum phosphorus (r = -0.40; P < .001). In subgroup analysis among non-whites, higher AR scores correlated with lower serum phosphorus (high vs lower AR score: 5.55 [1.5] vs 6.96 [2.2]; P = .01). Associations between AR score (ß 95% confidence interval: -0.37 [-0.73 to -0.01]; P = .04), medication adherence (ß 95% confidence interval: -0.25 [-0.42 to -0.07]; P = .01), and serum phosphorus persisted in adjusted analyses. CONCLUSIONS: Self-motivation was associated with phosphate binder adherence and phosphorus control, and this differed by race. Additional research is needed to determine if personalized, culturally sensitive strategies to understand and overcome motivational barriers may optimize mineral bone health in end-stage renal disease.

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.

Phosphorus binding with ferric citrate is associated with fewer hospitalizations and reduced hospitalization costs.

BACKGROUND: Ferric citrate (FC) is a new phosphorus binder shown to increase serum iron stores while reducing intravenous iron and erythropoiesis-stimulating agent usage. Such reductions could lower hospitalization rates and associated costs. METHODS: Hospitalizations during a Phase III trial were compared between FC and active control (AC). Hospitalization costs were estimated using the 2013 US Renal Data System Annual Data Report. RESULTS: 34.6% of FC patients were hospitalized at least once versus 45.6% of the AC group (risk reduction 24.2%; p = 0.02). There were 181 unique hospitalizations in the FC group versus 239 in the AC group, for a difference of 58 hospitalizations. Total potential savings was US$ 867,622 in hospitalization costs in the FC group. If the hospitalization reduction in our study was applied to the general end-stage renal disease population, this could translate into a savings of US$ 3002/patient/year. CONCLUSIONS: Patients receiving FC experienced fewer hospitalizations with the potential for significant savings.

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.