AIMS: Fibroblast growth factor 23 (FGF23) and Klotho are associated with vascular calcification and cardiovascular disease in dialysis patients. Sevelamer has been shown to reduce progression of vascular calcification. This study aimed to determine the long-term effect of sevelamer treatment on serum FGF23 and Klotho levels in chronic haemodialysis (HD) patients.
METHODS: In the post-hoc analysis, we measured serum FGF23, Klotho and other biochemical factors (Ca, P, i-PTH, hsCRP, LDL-C) in 50 haemodialysis patients, who completed a 48-week, open-Label, controlled randomized parallel-group study. Twenty-three patients received sevelamer and 27 patients received calcium carbonate.
RESULTS: After 48-week sevelamer treatment, there were significant changes with lower LDL-C (from 2.82 ± 0.78 to 1.65 ± 0.53 mmol/L, P = 0.000), lower FGF23 (from 2465.97 (2568.88) to 795.61 (1098.39), P = 0.000) and higher s-Klotho levels (from 189.35 (161.88) to 252.94 (517.80) pg/mL, P = 0.000). In calcium carbonate group, there were no significant changes of LDL-C and FGF23, but with a borderline significant increase of s-Klotho level (from 142.34 (265.24) to 188.57 (252.38) pg/mL, P = 0.054). Multivariate analysis showed that FGF23 decrement was associated with sevelamer treatment (β = -0.277, P = 0.005), change of serum phosphate (β = 0.609, P = 0.000) and calcium levels (β = 0.635, P = 0.000). The increase of serum Klotho was associated with the decrease of serum phosphate (β = 0.490, P = 0.019).
CONCLUSION: Maintenance HD patients had lower serum FGF23 levels, accompanied with significantly increased serum Klotho levels, after 48-week sevelamer treatment. The FGF23 decrement was associated with sevelamer use, the change of serum phosphate and calcium levels. The serum Klotho increment was proportional to the phosphate-lowering power of the binders.
ABSTRACT
Aim: To compare the effects of Sevelamer and calcium acetate on biomarkers of bone turnover in
patients of end stage renal disease (ESRD).
Methods: This was a prospective, randomized, open label study, total 140 patients of ESRD
underwent two week washout period and were divided randomly into two groups, Group A (received
Sevelamer) and Group B (received calcium acetate) for 24 weeks. Mean changes in the serum level of
calcium phosphorus and intact PTH were measured and compared.
Results: After 24 weeks of treatment there was significantly reductionof phosphorus in Group A as
compared with Group B (-1.764mg/dl vs.1.0600 p=0.000). Mean change in iPTH was more in Group B
as compared with Group A (-124.32pg/ml vs. –83.44 pg/ml, p=0.044). There is significant increase in
serum calcium level in Group B patients compared to Group A (0.688mg/dl vs. –0.126 mg/dl, p=0.000).
Conclusion: Sevelamer effectively reduces serum phosphorus with a lower incidence of rise in serum
calcium level in dialysis population, although more reduction of iPTH occurred in calcium acetate
group.
Key words: Savelmer hydrochloride, bone biomarkers, renal disease, hemodialysis
BACKGROUND: Hyperphosphataemia is a known independent risk factor for cardiovascular mortality. The objective of the study was to compare the effects of two phosphate binders, sevelamer carbonate and calcium carbonate on endothelial function (EF) and inflammation in patients on peritoneal dialysis (PD) with Type 2 diabetes mellitus (T2DM).
METHODS: Fifteen subjects with hyperphosphataemia discontinued all phosphate binders to undergo a two-week washout and were assigned to sevelamer carbonate or calcium carbonate treatments for eight weeks. After a second two-week washout period, subjects crossed over to either of the alternate treatments for another eight weeks. At the beginning and end of each treatment, biomarkers of EF, pro-inflammatory cytokines, serum albumin, calcium, phosphate and lipids were measured.
RESULTS: Sevelamer carbonate significantly improved lipid profile compared with calcium carbonate. Amongst the EF and pro-inflammatory biomarkers, sevelamer carbonate decreased serum endothelin-1, plasminogen activator inhibitor-1, C-reactive protein and interleukin-6. Both phosphate binders were effective in decreasing serum phosphate but sevelamer had a positive effect on EF.
CONCLUSIONS: Treatment with sevelamer carbonate has beneficial effects compared with calcium carbonate in decreasing inflammation and improving EF in patients with T2DM on PD.
BACKGROUND: Whether the use of sevelamer rather than a calcium-containing phosphate binder improves cardiovascular (CV) survival in patients receiving dialysis remains to be elucidated.
STUDY DESIGN: Open-label randomized controlled trial with parallel groups.
SETTINGS & PARTICIPANTS: 466 incident hemodialysis patients recruited from 18 centers in Italy.
INTERVENTION: Study participants were randomly assigned in a 1:1 fashion to receive either sevelamer or a calcium-containing phosphate binder (although not required by the protocol, all patients in this group received calcium carbonate) for 24 months.
OUTCOMES: All individuals were followed up until completion of 36 months of follow-up or censoring. CV death due to cardiac arrhythmias was regarded as the primary end point.
MEASUREMENTS: Blind event adjudication.
RESULTS: At baseline, patients allocated to sevelamer had higher serum phosphorus (mean, 5.6 ± 1.7 [SD] vs 4.8 ± 1.4 mg/dL) and C-reactive protein levels (mean, 8.8 ± 13.4 vs 5.9 ± 6.8 mg/dL) and lower coronary artery calcification scores (median, 19 [IQR, 0-30] vs 30 [IQR, 7-180]). At study completion, serum phosphate levels were lower in the sevelamer arm (median dosages, 4,800 and 2,000 mg/d for sevelamer and calcium carbonate, respectively). After a mean follow-up of 28 ± 10 months, 128 deaths were recorded (29 and 88 due to cardiac arrhythmias and all-cause CV death). Sevelamer-treated patients experienced lower CV mortality due to cardiac arrhythmias compared with patients treated with calcium carbonate (HR, 0.06; 95% CI, 0.01-0.25; P < 0.001). Similar results were noted for all-cause CV mortality and all-cause mortality, but not for non-CV mortality. Adjustments for potential confounders did not affect results.
LIMITATIONS: Open-label design, higher baseline coronary artery calcification burden in calcium carbonate-treated patients, different mineral metabolism control in sevelamer-treated patients, overall lower than expected mortality.
CONCLUSIONS: These results show that sevelamer compared to a calcium-containing phosphate binder improves survival in a cohort of incident hemodialysis patients. However, the better outcomes in the sevelamer group may be due to better phosphate control rather than reduction in calcium load.
BACKGROUND AND OBJECTIVES: Dietary phosphorous overload and excessive calcium intake from calcium-containing phosphate binders promote coronary artery calcification (CAC) that may contribute to high mortality of dialysis patients. CAC has been found in patients in early stages of nondialysis-dependent CKD. In this population, no study has evaluated the potential role of phosphorus binders on mortality. This study aimed to evaluate all-cause mortality as the primary end point in nondialysis-dependent CKD patients randomized to different phosphate binders; secondary end points were dialysis inception and the composite end point of all-cause mortality and dialysis inception.
DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This is a randomized, multicenter, nonblinded pilot study. Consecutive outpatients (n=212; stage 3-4 CKD) were randomized to either sevelamer (n=107) or calcium carbonate (n=105). Phosphorus concentration was maintained between 2.7 and 4.6 mg/dl for patients with stage 3-4 CKD and between 3.5 and 5.5 mg/dl for patients with stage 5 CKD. The CAC score was assessed by computed tomography at study entry and after 6, 12, 18, and 24 months. All-cause mortality, dialysis inception, and the composite end point were recorded for up to 36 months.
RESULTS: In patients randomized to sevelamer, all-cause mortality and the composite end point were lower; a nonsignificant trend was noted for dialysis inception.
CONCLUSIONS: Sevelamer provided benefits in all-cause mortality and in the composite end point of death or dialysis inception but not advantages in dialysis inception. Larger studies are needed to confirm these results.
BACKGROUND: Fibroblast growth factor 23 (FGF-23) is a marker of endothelial dysfunction and atherosclerotic complications in patients with chronic kidney disease (CKD). Because previous studies suggested that sevelamer may exert effects on FGF-23 level and endothelial function independently of its phosphate-lowering action, we tested the effect of sevelamer versus calcium acetate on vascular function and FGF-23 levels.
STUDY DESIGN: Randomized prospective open-label trial.
SETTING & PARTICIPANTS: Patients with stage 4 CKD with hyperphosphatemia (n = 100).
INTERVENTION: An 8-week intervention with sevelamer (n = 47) and calcium acetate (n = 53).
OUTCOMES: The primary study outcome was change in flow-mediated vasodilatation in the forearm. The secondary outcome was change in FGF-23 levels.
RESULTS: Serum phosphate levels decreased in both treatment arms (P < 0.001), but more markedly in the sevelamer group (P < 0.001). Flow-mediated vasodilatation increased from 6.1% to 7.1% (P < 0.001) in sevelamer-treated patients, whereas it was unchanged in the calcium-acetate group (6.0% vs 6.0%). In a combined analysis, treatment-induced changes in flow-mediated vasodilatation were (P < 0.001) associated with simultaneous changes in FGF-23 levels (-27.1% [-33.2% to -8.8%] for the sevelamer group; 3.5% [-8.4% to 12.1%] for the calcium acetate group), as well as with C-reactive protein and fetuin A levels. These relationships were confirmed in multiple regression analysis adjusting for changes in serum phosphate levels and other factors.
LIMITATIONS: Unblinded randomized controlled study that cannot establish mechanisms of effect.
CONCLUSIONS: In hyperphosphatemic patients with stage 4 CKD, treatment with phosphate lowering induces measurable improvements in flow-mediated vasodilatation. Furthermore, independently of serum phosphate level, FGF-23 level changes induced by phosphate binders are associated with simultaneous changes in flow-mediated vasodilatation. These observations are compatible with the hypothesis that FGF-23 may contribute to vascular dysfunction in this population.
Some propose using phosphate binders in the CKD population given the association between higher levels of phosphorus and mortality, but their safety and efficacy in this population are not well understood. Here, we aimed to determine the effects of phosphate binders on parameters of mineral metabolism and vascular calcification among patients with moderate to advanced CKD. We randomly assigned 148 patients with estimated GFR=20-45 ml/min per 1.73 m(2) to calcium acetate, lanthanum carbonate, sevelamer carbonate, or placebo. The primary endpoint was change in mean serum phosphorus from baseline to the average of months 3, 6, and 9. Serum phosphorus decreased from a baseline mean of 4.2 mg/dl in both active and placebo arms to 3.9 mg/dl with active therapy and 4.1 mg/dl with placebo (P=0.03). Phosphate binders, but not placebo, decreased mean 24-hour urine phosphorus by 22%. Median serum intact parathyroid hormone remained stable with active therapy and increased with placebo (P=0.002). Active therapy did not significantly affect plasma C-terminal fibroblast growth factor 23 levels. Active therapy did, however, significantly increase calcification of the coronary arteries and abdominal aorta (coronary: median increases of 18.1% versus 0.6%, P=0.05; abdominal aorta: median increases of 15.4% versus 3.4%, P=0.03). In conclusion, phosphate binders significantly lower serum and urinary phosphorus and attenuate progression of secondary hyperparathyroidism among patients with CKD who have normal or near-normal levels of serum phosphorus; however, they also promote the progression of vascular calcification. The safety and efficacy of phosphate binders in CKD remain uncertain.
BACKGROUND AND OBJECTIVES: Increased inflammation and oxidative stress may be caused by proteins and lipids modified by cytotoxic advanced glycation end products (AGEs) in food. Restricting food containing elevated AGEs improves these risk factors in diabetic CKD. Because diet adherence can be problematic, this study aimed to remove cytotoxic AGEs from food already ingested and to determine whether sevelamer carbonate sequesters cytotoxic AGEs in the gut, preventing their uptake and thereby reducing AGE-induced abnormalities.
DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This single-center, randomized, 2-month, open-label, intention-to-treat, crossover study compared sevelamer carbonate with calcium carbonate treatment in stage 2-4 diabetic CKD. Participants received 2 months of treatment with one drug, had a 1-week washout, and then received the opposite drug for 2 months.
RESULTS: Sevelamer carbonate reduced HbA1c, serum methylglyoxal, serum (ε)N-carboxymethyl-lysine, triglycerides, and 8-isoprostanes. Total cholesterol and fibroblast growth factor 23 were reduced by sevelamer carbonate, relative to calcium carbonate. AGE receptor 1 and sirtuin 1 mRNA were increased and PMNC TNFα levels were decreased by sevelamer carbonate, but not calcium carbonate. Medications and caloric and AGE intake remained unchanged. Sevelamer carbonate reversibly bound AGE-BSA at intestinal, but not stomach, pH.
CONCLUSIONS: Sevelamer carbonate significantly reduces HbA1c, fibroblast growth factor 23, lipids, and markers of inflammation and oxidative stress, and markedly increases antioxidant markers, independently of phosphorus in patients with diabetes and early kidney disease. These novel actions of sevelamer carbonate on metabolic and inflammatory abnormalities in type 2 diabetes mellitus may affect progression of early diabetic CKD.
BACKGROUND: Some trials have indicated that coronary artery calcification progresses more slowly in sevelamer-treated dialysis patients than in those using calcium-based binders. Effects of phosphate binders on circulating advanced glycation end products (AGEs) are unknown.
STUDY DESIGN: Randomized trial with parallel-group design.
SETTING & PARTICIPANTS: 183 adult (aged >20 years) patients on maintenance hemodialysis therapy at 12 dialysis facilities with a mean vintage of 118 ± 89 (median, 108) months. Dialysate calcium concentration was 2.5 mEq/L, and dietary calcium was not controlled.
INTERVENTION: Patients were randomly assigned to 12 months of treatment with sevelamer (n = 91) or calcium carbonate (n = 92).
OUTCOMES & MEASUREMENTS: Primary outcome measures were change from baseline in coronary artery calcification score (CACS) determined at study entry and completion using multislice computed tomography and the proportion of patients with a ≥ 15% increase in CACS. Blood parameters were determined at study entry and 2-week intervals, and levels of plasma pentosidine, a representative AGE, were determined at study entry, 6 months, and study completion.
RESULTS: 79 (86.8%) and 84 (91.3%) patients in the sevelamer and calcium-carbonate arms completed the treatment, respectively. Both binders were associated with an increase in mean CACS: 81.8 (95% CI, 42.9-120.6) and 194.0 (139.7-248.4), respectively (P < 0.001 for both). After adjustment for baseline values, the increase in the sevelamer group was 112.3 (45.8-178) less (P < 0.001). Percentages of patients with a ≥ 15% increase in CACS were 35% of the sevelamer group and 59% of the calcium-carbonate group (P = 0.002). Plasma pentosidine levels increased with calcium carbonate but not [corrected] sevelamer treatment (P < 0.001). Sevelamer use was associated with decreased risk of a ≥ 15% increase in CACS regardless of baseline blood parameters, pentosidine level, and CACS.
LIMITATIONS: Treatment duration was relatively short, some sevelamer-treated patients (7 of 79) received calcium carbonate, and washout could not be performed.
CONCLUSIONS: The data suggest that sevelamer treatment slowed the increase in CACS and suppressed AGE accumulation.
