Calcium Carbonate Treatment Research Articles

Possibility of application of calcium carbonate in pulpotomy of rat molars

We investigated restitution processes in mechanically exposed rat molar pulp during pulpotomy with calcium carbonate (CC). The results of the CC treatment were then compared with Calvital ® -containing calcium hydroxide (CH). Micro-computerized tomography (micro-CT), hematoxylin and eosin (H&E) staining and immunoreactivity for nestin, dentin matrix protein-1 (DMP-1) and osteopontin (OPN) were also analyzed. The increment of dentinlike calcified tissue in the pulp was observed by micro-CT. Both CC and CH groups induced pulpotomy resulted in changes associated with inflammation followed by progressive odontoblasts differentiation, dentin matrix secretion and dentin-like bridge formation. Necrotic layer formation and moderate to severe inflammation occurred during the early stages in the CH group. Necrotic layer formation was not observed in the CC group and only associated with mild to moderate inflammation. Immunoreactivity of nestin was observed earlier in the CC group than the CH group. In the CC group, immunoreactivity of DMP-1 was identified beneath the amputated site after 7 days, before increasing until 28 days, and immunoreactivity of OPN was observed in the dentin-like bridge at 28 days, which was also similar to the CH group. These findings suggested that the primary processes of reparative dentinogenesis after pulpotomy with CC may involve natural pulpal wound-healing mechanisms that are similar to the restitution processes observed during pulpotomy with CH. However, CC may prove to be less irritation and more calcified tissue formation than traditional CH-based materials when used as a pulpotomy agent.

炭酸カルシウム－第二リン酸カルシウム混合物の水熱処理による炭酸アパタイトブロックの調製 ―第2報―

炭酸カルシウム－第二リン酸カルシウム混合物の水熱処理による炭酸アパタイトブロックの調製 ―第2報―

炭酸カルシウム―第二リン酸カルシウム混合物の水熱処理による炭酸アパタイトブロックの調製（第3報）

炭酸カルシウム―第二リン酸カルシウム混合物の水熱処理による炭酸アパタイトブロックの調製（第3報）

Sevelamer Hydrochloride

Sevelamer (Renagel), an orally administered metal-free cationic hydrogel polymer/resin that binds dietary phosphate in the gastrointestinal (GI) tract, is approved for use in the US, Europe and several other countries for the treatment of hyperphosphataemia in adult patients with end-stage renal disease (ESRD) on haemodialysis or peritoneal dialysis.Clinical evidence shows that sevelamer was at least as effective as calcium acetate and calcium carbonate at controlling serum phosphorus, calcium-phosphorus product (Ca x P) and intact parathyroid hormone (iPTH) levels, but generally reduced serum calcium levels to a greater extent and was associated with a lower risk of hypercalcaemic episodes than calcium-based phosphate binders. Sevelamer appeared to slow the progression of cardiovascular calcification in patients with ESRD and also had a beneficial effect on serum low-density lipoprotein-cholesterol (LDL-C) levels. In patients receiving chronic haemodialysis, there was no between-group difference in all-cause mortality between sevelamer and calcium-based phosphate binder therapy in the primary efficacy analysis in the large (n >2100), 3-year DCOR trial; in the smaller (n = 109) nonblind RIND trial in patients new to dialysis, data suggest there is an overall survival benefit with sevelamer versus calcium-based phosphate binder treatment. The relative survival benefits and cost effectiveness of these phosphate binder therapies remains to be fully determined. Sevelamer treatment was generally as well tolerated as calcium acetate or calcium carbonate treatment. Overall, sevelamer is a valuable option for the management of hyperphosphataemia in patients with ESRD on haemodialysis.

The progression of coronary artery calcification in predialysis patients on calcium carbonate or sevelamer

Coronary artery calcification is more prevalent in dialysis patients than in patients without kidney disease and this is associated with high serum phosphorus. In this study, we evaluate the effect of calcium carbonate or sevelamer treatments on the progression of calcification in 90 predialysis patients. Inclusion criteria were stable serum calcium, phosphorus, parathyroid hormone, and a similar baseline total calcium score (TCS). These patients were not treated by phosphate binder, vitamin D, or statin. They were given low-phosphorus diets without or with daily calcium carbonate or sevelamer throughout the study that averaged 2 years. Baseline demographic or clinical characteristics along with biochemical parameters were not different among the three groups. The TCS significantly increased in patients on the low-phosphorus diet alone, to a lesser extent in calcium carbonate-treated patients, and not at all in sevelamer-treated patients. The progression of coronary calcification paralleled that of the calcium score. Our study shows that sevelamer treatment should not be restricted to dialysis patients; however, a larger study should be undertaken to confirm these results.

Sickle cell bone disease: Response to vitamin D and calcium

Bone disease with osteoporosis and osteomalacia are common in sickle cell disease (SCD). Some patients have vitamin D deficiency and low bone mineral density (BMD). The role of vitamin D and calcium supplementation to restore bone health in SCD has not been well studied. In 14 adults with SCD, we measured 25(OH)D (25-hydroxyvitamin D) and BMD at the femoral neck, lumbar spine, and distal third of the ulna plus radius, along with markers of bone resorption (CTx; C-terminal component of pro-collagen type I) and bone formation (osteocalcin) before and after 12 months of vitamin D(2) and calcium carbonate treatment. Pretreatment, all patients were vitamin D deficient with a mean 25(OH)D level of 11.6 [corrected] +/- 4 [corrected] ng/ml, had low BMD at the lumbar spine (L-spine), 0.87 +/- 0.11 g/cm(2) (mean Z-score of -2.6 3 +/- 0.71 SD and T score of -2.31 +/- 0.75 SD), femoral neck, 0.8 +/- 0.18 g/cm(2) (mean Z-score -1.36 +/- 0.84, T-score -1.14 +/- 0.75), and the distal radius and ulna, 0.6 +/- 0.17 g/cm(2) (mean Z-score -1.18 +/- 0.79, T-score -1.01 +/- 0.74) and had elevated CTx (0.87 +/- 0.5 ng/ml) and osteocalcin levels (12.3 +/- 3.7 ng/mul). After treatment, all patients corrected their 25(OH)D level (34.6 [corrected] +/- 11 [corrected] ng/ml) (P < 0.001) with a 3.6% +/- 3.9% increase in BMD at the L-spine (P = 0.009), 4.6% +/- 8.5% increase at the femoral neck (P = 0.05) and 6.5% +/- 12.6% increase at the distal radius plus ulna (P = 0.09). CTx, osteocalcin, and PTH(i) levels were unchanged. Treatment of adult SCD with vitamin D and calcium can restore 25(OH)D levels to normal and improve BMD, but, markers of bone resorption remained unchanged. Screening for vitamin D deficiency and BMD in SCD patients seems warranted.

Evolution of bone and plasma concentration of lanthanum in dialysis patients before, during 1 year of treatment with lanthanum carbonate and after 2 years of follow-up

Lanthanum carbonate (LC) has been proposed as a new phosphate binder. Presented here are the results from one centre that participated in a multicentre trial to assess the effect of treatment with LC and calcium carbonate (CC) on the evolution of renal osteodystrophy in dialysis patients. Bone biopsies were performed at baseline, after 1 year of treatment and after a further 2-year follow-up period to assess the lanthanum concentration in bone and plasma. Twenty new dialysis patients were randomized to receive LC (median dose 1250 mg) for 1 year (n = 10), followed by 2 years of CC treatment or CC (n = 10) during the whole study period (3 years). After 36 weeks of treatment, steady state was reached with plasma lanthanum levels varying around 0.6 ng/ml. Six weeks after cessation of 1 year of treatment, the plasma lanthanum levels declined to a value of 0.17 +/- 0.12 ng/ml (P < 0.05) and after 2 years to 0.09 +/- 0.03 ng/ml. Plasma and bone lanthanum levels did not correlate with the average lanthanum dose at any time point. The mean bone concentration in patients receiving LC increased from 0.05 +/- 0.03 to 2.3 +/- 1.6 microg/g (P < 0.05) after 1 year and slightly decreased at the end of the study to 1.9 +/- 1.6 microg/g (P < 0.05). Bone deposition after 1 year of treatment with LC is low (highest concentration: 5.5 microg/g). There is a slow release of lanthanum from its bone deposits 2 years after the discontinuation of the treatment and no association with aluminium-like bone toxicity.

New strategy to attenuate pulse wave velocity in haemodialysis patients

Pulse wave velocity (PWV) is commonly elevated in haemodialysis (HD) patients having cardiovascular diseases. Disturbances in calcium-phosphate metabolism are among the established cardiovascular risk factors in HD patients. The present study was performed to assess the effect of sevelamer on PWV in HD patients. Fifteen patients, who had been treated with calcium carbonate as a phosphate binder, were entered into the study. Changes in PWV during the 6 months before sevelamer administration were compared with PWV changes during 6 months of receiving sevelamer. Serum biochemistry parameters were also assessed. Compared with the preceding control period, the sevelamer period resulted in decreased serum calcium (9.9+/-0.1 to 9.6+/-0.1 mg/dl, n = 15; P<0.01) in association with reductions in oral calcium load (4.3+/-0.4 to 2.3+/-0.6 g/day; P<0.001). Serum phosphorus and whole parathyroid hormone remained unchanged. Sevelamer reduced serum total cholesterol (167+/-7 to 148+/-6 mg/dl; P<0.001) and LDL-cholesterol (85+/-8 to 65+/-7 mg/dl; P<0.001), without modifying HDL-cholesterol or triglycerides. Finally, sevelamer reversed the increase in PWV observed during the control period (from 46+/-16 to -20+/-9 cm/s/month; P<0.01). In chronic HD patients, sevelamer decreased serum total- and LDL-cholesterol as well as calcium. Moreover, our findings suggest that treatment with sevelamer attenuates the progressive increase in PWV observed during calcium carbonate treatment.

Combination Therapy with Sevelamer Hydrochloride and Calcium Carbonate in Japanese Patients with Long‐Term Hemodialysis: Alternative Approach for Optimal Mineral Management

Calcium (Ca) overload by Ca-containing phosphorus (P) binder has been suggested to be implicated in the pathogenesis of soft tissue and vascular calcification, which contribute to increased morbidity and mortality of cardiovascular disease in patients undergoing dialysis. Recently, a noncalcium P binder, sevelamer hydrochloride (sevelamer), has become available in Japan. However, Japanese patients undergoing dialysis might be less tolerant of sevelamer treatment, and it is likely to cause hypocalcemia because their dietary Ca intake is less than that in European and American patients. We evaluated the effects of combination therapy with sevelamer and calcium carbonate (CC) on mineral metabolism in Japanese hemodialysis patients, as an alternative form of P management. A total of 210 hemodialysis patients were enrolled, and were given a small dose of sevelamer (0.75-1.5 g/day) on CC treatment. Sevelamer dose was gradually increased, while CC decreased during 24 weeks. Five patients discontinued sevelamer treatment because of severe constipation, anorexia, and parathyroidectomy for severe secondary hyperparathyroidism. After 24 weeks, the dose of sevelamer was significantly increased to 3.29 g/day (initial dose: 1.47 g/day), while CC was decreased by 54%. Adjusted serum Ca significantly decreased (9.63 +/- 0.57-9.45 +/- 0.67 mg/dL; P = 0.0012), although serum P increased (5.89 +/- 1.32-6.25 +/- 1.32 mg/dL; P = 0.017). Serum intact PTH (iPTH) significantly increased in patients with a low or normal iPTH level (< or =300 pg/mL), while it did not change in patients with secondary hyperparathyroidism (>300 pg/mL). The results suggest that the therapeutic regimen is more tolerant and reduces Ca load in Japanese hemodialysis patients while avoiding hypocalcemia. In addition, the mitigated Ca overload could improve PTH hyposecretion in patients with adynamic bone disease, which is associated with soft tissue calcification and higher mortality in uremia.

Utilization of bone histomorphometry in renal osteodystrophy: demonstration of a new approach using data from a prospective study of lanthanum carbonate

The aim of this study was to develop a novel approach to the analysis of bone histomorphometric data and outcomes presentation that would simplify the characterization of renal osteodystrophy and facilitate clinical decision-making. Data were derived from a randomized trial of dialysis patients treated for one year with a dose of lanthanum carbonate or calcium carbonate (up to 3750 mg/day and 9000 mg/day, respectively). Histomorphometric analyses of baseline and end-of-study bicortical transiliac bone biopsies were performed. Activation frequency, bone formation rate/bone surface, osteoclast surface/ bone surface, osteoblast surface/bone surface, mineralization lag time, and osteoid thickness were determined to provide a measure of overall bone cell activity (bone formation, bone resorption, bone turnover) and risk of developing osteopenia (bone balance). A novel approach of qualitatively grouping these numerical data as "improved", "unchanged", or "worsened" based on deviation from normal was used to facilitate interpretation of clinical relevance. Using our method, lanthanum carbonate was shown to improve histomorphometric parameters measured. These improvements were superior to those produced by calcium carbonate. These data add valuable clinical relevance to the previously published qualitative data from the same cohort [D'Haese et al. 2003]. Lanthanum carbonate moderated extreme forms of renal osteodystrophy, whereas calcium carbonate treatment increased the incidence of adynamic and predominant hyperparathyroid bone disease. This study provides an approach to the prospective evaluation of bone disease progression with therapy, and its application supports the safety and greater efficacy of one-year lanthanum carbonate versus calcium carbonate therapy as a means to normalize bone turnover in dialysis patients.

Treatment of Acid Leachate from Coal Discard using Calcium Carbonate and Biological Sulphate Removal

An integrated approach is proposed for treating acidic coal discard leachate, consisting of CaCO3 handling and dosing, CaCO3-neutralization, and biological sulphate removal. It was found that: powdered CaCO3 can be slurried to a constant density and used to neutralize the acid water, remove Fe (II), Fe (III), and Al, and partially remove the sulphate (to saturation level); biological sulphate removal can be used to lower the sulphate to less than 200 mg/L using ethanol as the carbon and energy source; CO2 produced during calcium carbonate treatment can be used for H2S-stripping and; H2S gas recovered in the sulphate removal stage can be used for iron removal.

Sediment phosphorus dynamics for three tile fed drainage ditches in Northeast Indiana

Phosphorus (P) losses from agricultural lands degrade surface waters due to anthropogenic eutrophication. Previous studies focused on plot-to-field scale P loss and reductions from best management practices (BMP's), little information in intense agricultural catchments has been gathered on the dynamics influencing P beyond the edge of the field. This study was conducted to examine the phosphorus equilibrium between the water column and sediments in three tile fed drainage ditches in Northeast Indiana. Surface water and sediment samples were collected and analyzed for organic carbon (C), particle size and P from sites along three ditches with similar soils and land use at sites within each watershed draining approximately 300 and 1500 ha on each ditch. Organic C, silt and clay fractions of the bottom sediments decreased with increasing drainage area. Soluble P concentrations were low in Ditch A, but increased with increasing drainage area (0.02–0.05 mg P L −1). Overall, the P concentrations were higher in the Ditches B and C (0.06–0.09 mg P L −1). Exchangeable P, P partitioning index and equilibrium P concentrations (EPC o) decreased with increasing drainage area by as much as 95, 93 and 100%, respectively, except in one catchment area with a confined animal feeding operation between sampling points, where ExP and EPC o increased by 4 and 116%, respectively. Aluminum sulfate and calcium carbonate treatment of ditch sediments reduced exchangeable P and sediment EPC o in this study. Results from this study indicated some watershed characteristics, as well as sediment physiochemical properties, affect ditch sediment and water P equilibrium and buffering capacity. Furthermore, this study demonstrated that managers could potentially use chemical treatment of the ditches to increase the temporary retention of P in ditches and maybe reducing sediment P availability.

Interfacial interactions in calcium carbonate–polypropylene composites. 1: Surface characterization and treatment of calcium carbonate: A comparative study

AbstractCalcuium carbonate (CaCO3) was modified with two types of coupling agents based on fatty acid and titanate. The efficiency of the surface treatment was studied through a dissolution method. The change in surface properties was characterized by inverse gas chromatography at both infinite dilution and finite concentration. It was found that a small amount of coupling agents caused a drastic decrease in surface energy, which varied as a function of bonded coupling agents. The completely covered CaCO3 exhibited a surface of little polarity. Infrared analysis showed that stearic acid reacted extensively with the filler surface to produce chemically bound organic salt compound, in addition to the increase in peak intensity due to the methylene vibration of the alkyl chain. However, instead of directly observing the transesterification reaction between LICA 12 and the filler, only an increase in the peak intensity due to absorption of the phosphate stretching was detected.

Effects of Aeration and Chemical Treatments on Nutrient Release from the Bottom Sediment of Tropical Marine Shrimp Ponds

The effects of aeration, and addition of aluminum sulfate (alum) and calcium carbonate on the release of nutrients from shrimp pond bottom sediments to the overlying water were studied in laboratory using sediment-water systems. Soluble reactive phosphorus (SRP) concentrations in the water column showed a decreasing trend culminating with the lowest values after 21 days of experiment, indicating strong adsorption of SRP by the sediment. Aeration significantly (p<0.05) decreased SRP concentrations compared to tanks without aeration in 14 days. During the first seven days, the addition of alum and calcium carbonate significantly (p<0.05) enhanced the decrease of SRP in the water column both in the aerated and unaerated tanks. The addition of alum did not affect the water pH, probably due to high buffering capacity of the marine pond water. From day 14 onwards, SRP concentrations in the aerated alum and calcium carbonate treatments had significantly higher SRP than the unaerated systems, probably due to the positive correlation between P-release and mixing energy, and higher pH and nitrate values in the aerated systems. Total ammonia nitrogen significantly decreased with aeration and the addition of lime. Total ammonia was not detected after day 14 as it was probably oxidized to nitrite and nitrate, adsorbed to the sediment or lost to the atmosphere at high pH. Nitrite concentrations were high in unaerated tanks only during the first 14 days and remained low thereafter. Nitrate remained high throughout the experiment, as there was absence of phytoplankton uptake in the system. This study illustrated that aeration together with the addition of alum and calcium carbonate may help control the release of excessive SRP and ammonia from the pond bottom sediments and minimize the occurrence of eutrophication and water quality deterioration in shrimp ponds.

Cell-associated magnesium and QT dispersion in hemodialysis patients

Background: Impaired magnesium (Mg) homeostasis has been implicated in a variety of cardiovascular disturbances, including ventricular arrhythmias and changes in the interval between the onset of wave Q to the end of wave T (QT interval) on electrocardiogram. Cardiac arrhythmias are common in patients on hemodialysis therapy. Methods: We investigated the relationship between QT interval corrected for heart rate (QTc) dispersion and Mg content in peripheral blood mononuclear cells (PBMC) of chronic hemodialysis patients treated with high-dose calcium carbonate providing Mg in excess (group I; n = 18) or low-dose calcium carbonate and smaller Mg load (group II; n = 13). Results: Mean Mg content in PBMC of group I patients (27.9 ± 4.2 [SD] μmol/L/mg protein) was significantly greater than in group II patients (10.4 ± 4.1 μmol/L/mg protein; P < 0.05) and greater in both groups than in healthy control subjects (2.75 ± 0.6 μmol/L/mg protein; P < 0.05). Mean QTc dispersion was significantly longer (74.6 ± 21.4 milliseconds) in group I than group II (37.8 ± 13.1 milliseconds; P < 0.02) and longer in both groups than in controls (27.3 ± 9.6 milliseconds; P < 0.05). After dialysis, in both groups of patients, cell-associated Mg (c-a Mg) levels and QTc dispersion were significantly greater (P < 0.05) than before dialysis started. One week after stopping calcium carbonate treatment, group 1 patients showed significant reductions in predialytic c-a Mg levels (to 19.5 ± 9.8 μmol/L/mg protein; P < 0.05) and QTc dispersions (to 48.9 ± 23.7 milliseconds; P < 0.05). Plasma Mg and other electrolyte concentrations prior to and during hemodialysis did not correlate with QTc dispersion. Conclusion: Prolongation of QTc dispersion in patients on chronic hemodialysis therapy could be, at least in part, a consequence of increased concentrations of c-a Mg resulting from excess daily Mg intake. Am J Kidney Dis 41:196-202. © 2003 by the National Kidney Foundation, Inc.

Chemical amelioration of high phosphorus availability in soil to aid the restoration of species-rich grassland

Whilst removal of phosphorus (P) by vegetation harvest can take decades to reduce plant-available soil P significantly, chemical amelioration offers a possible method of reducing P availability more rapidly by immobilizing P in a form unavailable for plant uptake. A replicated block experiment was established on two field sites using treatments of aluminium sulphate, elemental sulphur (S) and calcium carbonate to investigate the possibility of reducing P availability. Five plant species typical of wet grasslands were transplanted into the treated soil to investigate the effect of the treatments on species diversity. The results show that P availability in 0.15 m topsoil was significantly reduced by aluminium sulphate initially by 47% at site 1 and by 33% at site 2, with the effect persisting for the 15-month experimental period. P availability was increased at site 2 by the high dose elemental S treatment by 11%. Site 1 showed a similar trend in the S treatment but the trend was not significant. P availability was not affected by the calcium carbonate treatment. Botanical diversity was not increased by any of the treatments and was initially decreased by the aluminium sulphate treatment at both sites. This could have been due to the associated reduction in pH, which favored the dominant species, Holcus lanatus.

Effect of Phosphate Binders on Supplemental Iron Absorption in Healthy Subjects

A single‐dose, prospective, randomized, four‐treatment, four‐period crossover study was conducted to determine the acute effect of therapeutically equivalent doses of three commonly used phosphate binders on oral iron absorption. Twenty‐three healthy subjects received 65 mg of elemental iron alone and with each phosphate binder (calcium carbonate 3000 mg, calcium acetate 2668 mg, or sevelamer HCl 2821 mg). Area under the change in plasma iron concentration‐time curve over 6 hours postdosing was measured. ANOVA was used to assess the statistical significance of differences in iron absorption among the treatments. The relative bioavailability of iron administered with each phosphate binder compared to iron administered alone was estimated. The relative iron bioavailabilities (95% confidence intervals) for the calcium carbonate, calcium acetate, and sevelamer HCl treatments were 0.81 (0.70, 0.94), 0.73 (0.63, 0.85), and 0.90 (0.78, 1.05), respectively. Thus, single doses of both calcium‐based phosphate binders significantly reduced single‐dose iron absorption, while sevelamer HCl did not.

EFFECTS OF CALCIUM AND MAGNESIUM ON URINARY OXALATE EXCRETION AFTER OXALATE LOADS

Urinary oxalate is a primary determinant of the level of calcium oxalate saturation and the formation of calcium oxalate crystals, a key event in kidney stone formation. The primary objective of this study was to compare the effects of calcium carbonate and magnesium oxide on oxalate absorption. An experimental model was used that allowed differentiation between endogenously and oxalate load-derived urinary oxalate. Twenty-four healthy subjects (10 males, 14 females) participated in three oxalate load (OL) tests: control (OL alone), calcium carbonate (OL with concomitant calcium carbonate ingestion), and magnesium oxide (OL with concomitant magnesium oxide ingestion). Oxalate loads consisted of 180 mg. unlabeled and 18 mg. 1,2[13C2] oxalic acid. Timed urine samples were collected after the OL for analysis of oxalate, calcium, magnesium, and creatinine. Both the calcium carbonate and magnesium oxide treatments were associated with significantly lower load-derived oxalate levels at all time points within the initial 24-hour post-oxalate ingestion period compared with levels observed for the control treatment. There were no treatment effects on endogenous oxalate levels. The efficiency of oxalate absorption for the calcium carbonate (5.1%) and magnesium oxide (7.6%) treatments was significantly lower than that for the control treatment (13.5%). The results suggested that magnesium was nearly as effective as calcium in reducing oxalate absorption and urinary excretion. Higher levels of urinary oxalate, calcium, and magnesium in males appeared to be largely a function of body size since gender differences either disappeared or were reversed when a correction was made for urinary creatinine excretion.

Effects of Frequent, Small Doses of Calcium Carbonate on Water Quality and Phytoplankton in Channel Catfish Ponds

Abstract Finely pulverized calcium carbonate was added to 0.04-ha ponds at Auburn, Alabama, three times per week between 1 July and 11 October 1997 at 8 kg/ha for each application. Channel catfish Ictalurus punctatus were stocked and fed, and ponds were aerated 6 h each night following usual commercial practices. Calcium carbonate treatment reduced phytoplankton activity apparently through precipitation of soluble reactive phosphorus as calcium phosphate. There was less net oxygen production by phytoplankton in the ponds treated with calcium carbonate than in control ponds, but calcium carbonate treatment did not reduce cyanobacteria abundance. Small, frequent doses of calcium carbonate did not appear useful as a pond treatment for controlling phytoplankton and stabilizing water quality under the conditions existing in this study.

Control of hyperphosphatemia in regular hemodialysis (HDx) patients by calcium acetate (CA) versus calcium carbonate (CC). A double blind crossover prospective study

This study included fourty chronic renal failure patients aged 37-83 years (mean 51.3±7) on thrice weekly HDx for 4-144 month (Kt/V >1.2). Acetate dialysate with calcium concentration of 3 mEq/L was used. All phosphate binders were discontinued for one month. Patients were divided in two groups. Group I (20 cases) received CA, while group II (20 cases) received CC in equimolar dose (10 mmol, of either t.i.d.) for one month. Crossover of treatment was done for another month while keeping patients on the same diet. Serum levels of total calcium (Ca), ionized Ca (iCa), phosphorus (P), alkaline phosphates (AP), urea (U), creatinine (Cr), ALT, AST, total proteins (TP) and albumin (Alb) were estimated before, and at the end of each month of CA and CC treatment. Serum Ca and iCa were significantly lower in group I after CA compared to values after CC (p 0.05 in all). We excluded 12.5% of cases due to CA intolerance while non of cases had similar intolerance to CC. Conclusion: 1) CA is not very superior to CC in control of hyperphosphataemia. 2) CA can be safely increased without the risk of hypercalcemia. 3) Active Vitamin D and high dialysate Ca can be used to suppress parathyroid activity more safely with CA than with CC. 4) Tolerability to CC is superior.