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.