Johnson D W, Rigby R J, McIntyre H D, Brown A, Freeman J
Department of Nephrology, Princess Alexandria Hospital, Brisbane, Australia.
Nephrol Dial Transplant. 1996 Jan;11(1):88-93.
Effective control of hyperparathyroidism and renal osteodystrophy in CAPD patients requires a combination of calcitriol and calcium carbonate (CaCO3), but is frequently limited by hypercalcaemia. Reducing dialysate calcium (Ca) concentration may overcome this problem, but had not been examined in a controlled trial.
45 stable CAPD patients were randomly assigned in a prospective double-blind trial to either a study group (1.25 mmol/l Ca dialysate) or a control group (1.75 mmol/l Ca dialysate) for 12 months. Clinical, biochemical and radiological parameters of secondary hyperparathyroidism were followed.
Twenty-three patients did not complete the study due to death (9), transplantation (7) or conversion to haemodialysis (7). Eleven patients in each group completed the study. Mean serum Ca, phosphate, ionized Ca, aluminium, alkaline phosphatase (AP), and bone mineral density (BMD) Z-scores did not differ significantly at any time within or between the two groups. Severe hypercalcaemia was more common in the control group (11 vs. 2, P = 0.027). Mean serum intact parathyroid hormone (PTH) and osteocalcin (OCN) initially rose in the study group relative to controls at 3 months (40 +/- 7 vs 12 +/- 3 pmol/l, P = 0.004, and 33 +/- 5 vs 15 +/- 2 micrograms/l, P = 0.002 respectively), but were not sustained. Median weekly dosages of calcitriol and daily dosages of CaCO3 increased significantly in the study group (O microgram to 1 microgram P = 0.014 and 1260 mg to 2520 mg P = 0.002 respectively), but not in the control group. Supplementary aluminium hydroxide (A1, (OH)3) was required for phosphate control in both study (n = 5) and control patients (n = 4).
Lowering dialysate calcium concentration reduced the frequency of severe hypercalcaemia and allowed prescription of larger quantities of calcitriol and CaCO3. However, in this study it offered no advantage in terms of A1(OH)3 requirement, while bone mass density did and may have initially exacerbated secondary hyperparathyroidism not change.
持续非卧床腹膜透析（CAPD）患者甲状旁腺功能亢进和肾性骨营养不良的有效控制需要骨化三醇和碳酸钙（CaCO₃）联合使用，但常因高钙血症而受限。降低透析液钙（Ca）浓度可能会克服这一问题，但尚未在对照试验中进行研究。
45例稳定的CAPD患者在前瞻性双盲试验中被随机分为研究组（透析液钙浓度1.25 mmol/l）或对照组（透析液钙浓度1.75 mmol/l），为期12个月。对继发性甲状旁腺功能亢进的临床、生化和放射学参数进行跟踪。
23例患者因死亡（9例）、移植（7例）或转为血液透析（7例）未完成研究。每组11例患者完成研究。两组内及两组间在任何时间点的平均血清钙、磷、离子钙、铝、碱性磷酸酶（AP）和骨矿物质密度（BMD）Z评分均无显著差异。严重高钙血症在对照组更常见（11例对2例，P = 0.027）。研究组平均血清完整甲状旁腺激素（PTH）和骨钙素（OCN）在3个月时相对于对照组最初升高（分别为40±7对12±3 pmol/l，P = 0.004，以及33±5对15±2 μg/l，P = 0.002），但未持续。研究组骨化三醇的每周中位剂量和碳酸钙的每日剂量显著增加（分别从0 μg增至1 μg，P = 0.014，以及从1260 mg增至2520 mg，P = 0.002），而对照组未增加。研究组（n = 5）和对照组患者（n = 4）均需要补充氢氧化铝（Al(OH)₃）来控制磷。
降低透析液钙浓度可降低严重高钙血症的发生率，并允许使用更大剂量的骨化三醇和碳酸钙。然而，在本研究中，就氢氧化铝的需求而言，它没有优势，而骨密度没有变化，且可能最初会加重继发性甲状旁腺功能亢进。
