Spasovski Goce, Gelev Saso, Masin-Spasovska Jelka, Selim Gjulsen, Sikole Aleksandar, Vanholder Raymond
Department of Nephrology, Clinical Center Skopje, University of Skopje, Vodnjanska 17, 1000 Skopje, Macedonia.
Bone. 2007 Oct;41(4):698-703. doi: 10.1016/j.bone.2007.06.014. Epub 2007 Jun 29.
The existence of adynamic bone disease (ABD) as most prevalent form of renal osteodystrophy in recent years and its reduced ability to handle an exogenous calcium load has implied a higher risk for vascular and soft-tissue calcifications. The effect of low dialysate calcium (LCD) on parathyroid hormone (PTH) secretion in ABD patients has not yet sufficiently been clarified. This randomized, prospective study aimed to compare the effects of LCD and high calcium dialysate (HCD) on the evolution of bone and mineral parameters related to ABD in dialysis patients.
52 out of 60 patients with predialysis intact PTH<100 pg/ml completed this study and were equally distributed over LCD (1.25 mmol/l) or HCD (1.75 mmol/l) treatment. The duration of the study was 6 months and the only peroral phosphate binder administered was calcium carbonate. Total and ionised calcium were measured monthly in serum before and after dialysis while serum parameters relevant to bone were measured at the enrollment and at 3-month intervals.
There were no differences in predialysis mean phosphate or calcium x phosphorus product (Ca x P). The most common side effects of both treatments were comparable. Hypotension occurred in 16% and 17% and cramps in 6% and 8% of the dialysis sessions, in the HCD and LCD group, respectively. The groups did not differ in the mean tCa before dialysis, but this parameter was significantly higher in the HCD group vs. LCD at the end of dialysis (2.59+/-0.18 vs. 2.44+/-0.19 mmol/l; p<0.01). The patients of the HCD group also had a significantly higher mean iCa both before (1.08+/-0.05 vs. 1.04+/-0.06 mmol/l; p=0.02) and at the end of dialysis (1.18+/-0.04 vs. 1.48+/-0.04 mmol/l; p<0.01). There were no differences within the LCD group between baseline and end of dialysis treatment values of tCa and iCa. However, the mean tCa and iCa were markedly increased at the end of dialysis in the HDC group [2.40+/-0.21 vs. 2.59+/-0.18 mmol/l (p<0.01); 1.08+/-0.05 vs. 1.18+/-0.04 mmol/l (p<0.01)]. Mean serum levels of iPTH and total alkaline phosphatase in the LCD group were increased at 3 months and at the end of the study compared with the baseline levels [(38.6+/-22.9 vs. 63.3+/-46.0 vs. 78.6+/-44.7 pg/ml); (59.5+/-18.7 vs. 75.9+/-26.7 vs. 84.0+/-35.4 U/l)], respectively, and bone alkaline phosphatase increased also only after 6 months of treatment (23.4+/-7.3 U/l vs. 35.6+/-22.3). The bone markers in the HCD group did not change. At the end of the study all bone parameters in the LCD group were significantly higher than in the HCD group.
There was an evolution towards parameters reflecting higher bone turnover in patients treated with dialysate calcium of 1.25 mmol/l, probably by prevention of a positive calcium balance and enabling sustained stimulation of PTH secretion. Hence, LCD might be considered a valuable therapeutic option for ABD patients.
近年来，动力缺失性骨病（ABD）作为肾性骨营养不良最常见的形式存在，且其处理外源性钙负荷的能力下降，这意味着血管和软组织钙化风险更高。低钙透析液（LCD）对ABD患者甲状旁腺激素（PTH）分泌的影响尚未得到充分阐明。这项随机、前瞻性研究旨在比较LCD和高钙透析液（HCD）对透析患者与ABD相关的骨和矿物质参数变化的影响。
60例透析前完整PTH<100 pg/ml的患者中有52例完成了本研究，并被平均分配接受LCD（1.25 mmol/l）或HCD（1.75 mmol/l）治疗。研究持续时间为6个月，唯一口服的磷结合剂是碳酸钙。透析前后每月测定血清总钙和离子钙，而与骨相关的血清参数在入组时和每隔3个月测定一次。
透析前平均磷酸盐或钙磷乘积（Ca×P）无差异。两种治疗最常见的副作用相当。HCD组和LCD组分别有16%和17%的透析疗程出现低血压，6%和8%出现痉挛。两组透析前的平均总钙无差异，但透析结束时HCD组的该参数显著高于LCD组（2.59±0.18 vs. 2.44±0.19 mmol/l；p<0.01）。HCD组患者透析前和透析结束时的平均离子钙也显著更高（1.08±0.05 vs. 1.04±0.06 mmol/l；p=0.02）以及（1.18±0.04 vs. 1.48±0.04 mmol/l；p<0.01）。LCD组透析治疗开始时和结束时的总钙和离子钙值无差异。然而，HDC组透析结束时平均总钙和离子钙显著升高[2.40±0.21 vs. 2.59±0.18 mmol/l（p<0.01）；1.08±0.05 vs. 1.18±0.04 mmol/l（p<0.01）]。与基线水平相比，LCD组的平均血清离子PTH水平和总碱性磷酸酶在3个月时和研究结束时升高[（38.6±22.9 vs. 63.3±46.0 vs. 78.6±44.7 pg/ml）；（59.5±18.7 vs. 75.9±26.7 vs. 84.0±35.4 U/l）]，骨碱性磷酸酶也仅在治疗6个月后升高（23.4±7.3 U/l vs. 35.6±22.3）。HCD组的骨标志物未改变。研究结束时，LCD组的所有骨参数均显著高于HCD组。
接受1.25 mmol/l透析液钙治疗的患者，其反映骨转换率更高的参数出现变化，可能是通过防止钙正平衡并持续刺激PTH分泌实现的。因此，LCD可能被认为是ABD患者的一种有价值的治疗选择。
