LOW DIALYSATE CALCIUM IN CONTINUOUS AMBULATORY PERITONEAL-DIALYSIS - A RANDOMIZED CONTROLLED MULTICENTER TRIAL

Hypercalcemia is a common complication in continuous ambulatory perito neal dialysis (CAPD) patients treated with calcium-containing phosphat e binders and using the standard dialysate calcium concentration of 3. 5 mEq/L (SCa), Lowering the dialysate calcium was proposed to overcome this problem. The current randomized controlled multicenter study was designed to investigate efficiency end safety of a low calcium dialys ate (2.00 mEq/L; LCa) compared (with SCa (3.5 mEq/L) in CAPD patients, After an and week run-in period, 103 stable CAPD patients, 68 men, 35 women, aged 54.5 years (range, 20 to 77)) were randomly allotted to t reatment with either LCa or SCa. All patients received calcium carbona te as oral phosphate binder to achieve serum phosphate levels < 6.2 mg /dL. If persistent hypercalcemia arose, CaCO3 was replaced by Al(OH)(3 ) until normocalcemia was achieved. All patients received 0.25 mu g ca lcitriol/d. Parameters monitored included total and ionized serum calc ium, serum phosphate, phosphate binder intake, incidence of hypercalce mia, serum aluminium, intact parathyroid hormone (1,84PTH), osteocalci n, alkaline phosphatase, bone mineral density and hand skeletal x-ray, Primary end points were (a) number of hypercalcemic episodes, (b) tol erated doses of calcium-containing phosphate binders, and (c) 1,84PTH. After 6 months of therapy, total and ionized calcium were lower in LC a patients (total Ca:9.6 v 10.08 mEq/L, P = 0.005; iCa: 4.76 v 5.15 mg /dL; P = 0.013). In the LCa group, significantly fewer episodes of hyp ercalcemia were recorded (total S-calcium > 10.8 mg/dL: LCa 24 v SCa 8 6 episodes; P < 0.005). Use of LCa permitted the administration of mor e CaCO3 (mean daily tablet number: LCa, 5.9 v SCa, 4.2; P < 0.05). Mor e AI(OH)(3) was required in the SCa group (2.0 v 0.7 tablets/d per pat ient; P < 0.01). Control of serum phosphate was comparable, and initia l and final serum levels did not differ between the groups. 1,84 PTH l evels were within the desired range in the LCa group (medians: start o f run-in, 15 pmol/L; start of therapy, 15.5 pmol/L; wk 24, 14 pmol/L), whereas in the SCa group, 1,84 PTH declined to the normal range (star t of run-in, 15 pmol/l; start of therapy, 9.2; wk 24, 7.05 pmol/L; nor mal, 1 to 6 pmol/L). No radiologic signs of renal osteodystrophy or de mineralization of the bones were observed with LCa. Adverse events wer e rare, with the exception of peritonitis. The frequency of peritoniti s episodes and exit-site infections was similar, however, in LCa and S Ca patients. In conclusion, this randomized controlled multicenter stu dy in a large number of CAPD patients documents significantly better t olerance of calcium-containing phosphate binders with no adverse effec ts on PTH levels or other end points after 6 months of treatment when dialysate calcium concentration is lowered to 2.0 mEq/L. (C) 1995 by t he National Kidney Foundation, Inc.