Higher Proportion of Non-1-84 PTH Fragments in Peritoneal Dialysis Patients Compared to Hemodialysis Patients Using Solutions Containing 1.75 mmol/l Calcium.

Background: The prevalence of low- turnover bone disease (LTBD) in peritoneal dialysis (PD) patients is higher than in hemodialysis (HD) patients. LTBD patients may be at risk for vascular calcification, and cardiovascular disease. Current therapy for chronic kidney disease metabolic bone disorders (CKD-MBD) is guided by biochemical parameters, as bone biopsy is not used in routine clinical care. Methods: We assessed intact PTH (iPTH: 1-84PTH plus non-1-84PTH), 1-84PTH, and the 1-84PTH/non-1-84PTH ratio in 129 hemodialysis and 73 PD prevalent patients dialyzed with solutions containing 1.75 mmol/L calcium. Results: Hemodialysis and PD patients presented similar iPTH and tCa values and prevalence of putative LTBD as defined according to KDOQI iPTH cut-off levels or 1-84 PTH levels. However, iCa accounted for a higher percentage of tCa in PD (53%) than in hemodialysis (39%) p < 0.001, and the 1-84PTH/non-1-84PTH ratio was lower in PD than in hemodialysis patients (0.44 ± 0.12) vs. (0.60 ± 0.10), p < 0.001. The prevalence of putative LTBD when using the coexistence of 1-84PTH/non-1-84PTH ratio < 1.0 and iPTH < 420 pg/m, was higher in PD than in hemodialysis patients (73 vs. 16% respectively, p < 0.001). In a multivariate logistic regression analysis, dialysis modality was the main determinant of the 1-84PTH/non-1-84PTH ratio. Conclusion: Solutions containing 1.75 mmol/L calciums are associated to a higher proportion of non-1-84PTH fragments in PD than in HD patients. Different analytical criteria result in widely different estimates of LTBD prevalence, thus impairing the ability of clinicians to optimize therapy for CKD-MBD.

The influence of low calcium dialysate on left ventricular diastolic function in peritoneal dialysis patients.

Left ventricular (LV) diastolic function was found to be a significant predictor of cardiovascular events and general mortality in dialysis. Studies have indicated that dialysate calcium concentrations were significantly associated with cardiac function. However, the relationship between low calcium dialysate and LV diastolic function has not been clear. The aim of this study was to investigate the influence of low calcium dialysate on cardiac function in peritoneal dialysis (PD) patients. A total of 60 PD patients were enrolled in this study, with a calcium content of the PD solution of 1.25 mmol/L in 30 patients (low-calcium group) and 1.75 mmol/L in 30 patients (standard-calcium group). Standard M-mode and two-dimensional ultrasound measurements were applied to detect the cardiac function. After 12-month follow-up, we found no significant difference in blood pressure, calcium, phosphorus, parathyroid hormone (PTH), etc., between the two groups. Residual renal function (RRF), which is associated with LV cardiac function, was significantly decreased in the standard-calcium group compared with the low-calcium group (5.64 ± 3.23 vs. 9.38 ± 3.17, p = .001). Compared with the low-calcium group, Emax (peak early diastolic velocity) and Amax (peak late diastolic velocity) were significantly decreased (p < .05), whereas myocardial performance index (MPI) was obviously increased in standard-calcium group (9.69 ± 2.71 vs. 7.75 ± 0.93, p < .05). In conclusion, our data suggest that low calcium dialysate treatment is significantly associated with better LV diastolic function.

Long term effects on mineral and bone metabolism by low versus standard calcium dialysate in peritoneal dialysis: a meta-analysis.

BACKGROUND: Low calcium dialysate with 1.25 mmol/l calcium concentration has been proposed to replace standard calcium dialysate in peritoneal dialysis patients taking calcium-containing phosphate binder to prevent hypercalcaemia. We conducted a meta-analysis to evaluate long term effects on mineral and bone metabolism by low versus standard calcium dialysate in peritoneal dialysis. METHOD: Clinical studies comparing low versus standard calcium dialysate in peritoneal dialysis patients were identified by searching PubMed (from 1990 to October 2013) and EMBASE (from 1990 to October 2013). Major outcomes extracted for meta-analysis were: serum total and ionized calcium, phosphate, parathyroid hormone and bone metabolism. Statistical analyses were performed using the Review Manager, version 5.1.0 (Cochrane Collaboration, Oxford, UK). RESULTS: Four studies were identified for meta-analysis. A total of 240 peritoneal dialysis patients received standard calcium dialysate and 106 patients were given low calcium dialysate. 1-2 year after peritoneal dialysis, both serum total and ionized calcium were lower in low calcium dialysate patients as compared with standard dialysate patients (Total calcium: MD, 0.09; 95% CI, 0.05 0.13; P < 0.0001; Ionized calcium: MD, 0.04; 95% CI, 0.02 0.06; P < 0.0001). No statistical difference was observed in phosphate level between two groups (MD, -0.05; 95% CI, -0.13 0.02; P = 0.19). Intact parathyroid hormone level was significantly increased in low calcium dialysate patients. No clinically significant long term change of bone metabolism was observed between low and standard calcium dialysate treated patients. CONCLUSION: Long term (1-2 year) use of low calcium dialysate with 1.25 mmol/l calcium concentration in peritoneal dialysis patients results in decrease of serum total and ionized calcium level and does not change serum phosphate level. No clinical significance in the change of bone metabolism was observed between low and standard calcium dialysate patients despite the increase of serum parathyroid hormone in low calcium dialysate group.

Clinical Usefulness of Low Calcium Dialysate in CAPD Patients with High Risk of Low-turnover Bone Disease / 대한신장학회잡지

Hypercalcemia is a common complication in CAPD patients treated with calcium-containing phosphate binders and using the standard dialysate(Ca++ : 3.5 mEq/L). Furthermore, the high calcium concentration in standard dialysate may have a suppressive effect on parathyroid hormone(iPTH) level, contributing to the high prevalence of low-urnover bone disease. We studied the effect of low calcium dialysate(Ca++ : 2.5 mEq/L) for those patients with high risk of low- turnover bone disease. Among 386 patients(1996. 1.- 1999. 12.) who had been stable on CAPD for at least 3 months, 46 patients were included in this study. The patients were divided into 3 groups on the basis of the iPTH levels(10 mg/dL) before the conversion to low calcium dialysate. Group 1(n=29), iPTH 10 mg/dL; Group 2 (n=14), iPTH 150 pg/mL and Ca++ >10 mg/ dL. During a 2-month run-in period, those patients were treated with standard dialysate. After that, a 12-month therapy with low calcium dialysate was followed. Biochemical data including calcium, phosphorus, iPTH and alkaline phosphatase were measured regularly and daily phosphate binder and calcitriol intake(pill counting) were assessed during the run-in and therapy period. We obtained the following result: the prevalence of hypercalcemia(Ca++>10.5 mg/dL) was 5.7%(22/ 386 patients). Serum calcium levels decreased during the therapy period(12 months)(10.5+/-1.4 vs 9.4+/-1.3 mg/dL, p<0.05). Serum phosphorus levels remained unchanged. Mean serum alkaline phosphatase level increased(203.0+/-92.9 vs 257.2+/-103.4 U/L, p<0.05). Serum iPTH levels increased (92.7+/-128.8 vs 225.3+/-237.3 pg/mL,p<0.05). The mean intake of oral phosphate binders was not significantly different between run-in period and therapy period. But calcitriol doses increased 0.038+/-0.087 at run-in period to 0.158+/-0.288 tablets/person/day at therapy period(p<0.05). In the six patients, low calcium dialysate was converted to standard dialysate due to high iPTH level (n=3), symptomatic hypo calcemia(n=2), and uncontrolled edema(n=1). In conclusion, in the study of 46 patients over 12 month period, the usage of 2.5 mEq/L calcium dialysate resulted in a significant decrement in calcium levels and increased iPTH levels. Therefore, we propose that dialysis with a low calcium dialysate is an acceptable form of therapy for the patients with high risk of low-turnover bone disease showing hypercalcemia and low iPTH level. However, further study will be needed for evaluating the effect of low calcium dialysate in low-turnover bone disease.

Clinical Usefulness of Low Calcium Dialysate in Continuous Ambulatory Peritoneal Dialysis (CAPD) Patients / 대한신장학회잡지

Hypercalcemia is a common complication in CAPD patients treated with calcium-containing phosphate binders and using the standard dialysate (SCD) calcium concentration of 3.5mEq/L. We performed a retrospective study in 25 CAPD patients to determine whether a low calcium dialysate (LCD) containing 2.5mEq/L calcium would reduce the incidence of hypercalemia with adequate control of serum inorganic phosphate levels and diminish the need to use aluminum-containing phosphate binders. All patients had previously used SCD before converting to LCD. The incidence of hypercalcemia (more than 2 episodes of corrected serum calcium > or = 10.5mg/dL) tended to be lower after converting to LCDl 0.27 (0-2.76) vs. 0 (0-1.97) episodes/patient-yearl. Intact PTH level increased from 38.8 (0.1-1599.3)pg/mL to 70.6 (9.5-1540.0)pg/mL after conversion, but there was no statistical sifnificance. Serum calcium, inorganic phosphate, alkaline phosphatase and bicarbonate levels did not change after converting to LCD. We were able to reduce aluminum hydroxide dosagel 1.09 (0-10.88) vs. 0 (0-3.26)g/day/patientl and increase calcium carbonate dosage (1.95 0.92 vs. 2.98 2.14g/day/ patient) after conversion significantly (P<0.05). The frequency of peritonitis was similar in LCD and SCD period. In conclusion, low calcium dialysate is useful in diminishing aluminum-containing phosphate binder dosage and increasing calcium carbonate dosage to maintain a similar phosphate value. Its effects on renal osteodystrophy remain to be assessed.