Supplementary Material for: Mineral Metabolism Management in Hemodialysis Patients with Secondary Hyperparathyroidism in Japan: Baseline Data from the MBD-5D

Background/Aims: The Mineral and Bone Disorder Outcomes Study for Japanese CKD Stage 5D Patients (MBD-5D) is a multicenter, prospective observational study of hemodialysis patients with secondary hyperparathyroidism (SHPT) in Japan, where the national guideline recommends targets for serum calcium (8.4–10.0 mg/dl), phosphorus (3.5–6.0 mg/dl), and intact parathyroid hormone (PTH) (60–180 pg/ml). Methods: The MBD-5D involved patients who were receiving hemodialysis for more than 3 months and met at least one of the following conditions: having intact PTH levels >180 pg/ml, or receiving intravenous vitamin D receptor activators (VDRAs) or oral VDRA analog. This report describes the baseline characteristics of the study participants and examines factors associated with mineral metabolism controllability. Results: A total of 8,229 patients were registered from 86 facilities as the whole cohort, and 3,276 patients were randomly selected as the subcohort. The severity of SHPT was associated with a lower likelihood of achieving the targets for calcium and phosphorus, whereas patients with a history of parathyroidectomy were more likely to achieve these targets as compared with those who had not undergone surgery despite high PTH levels. The use of 2.5 mEq/l calcium dialysate was also associated with a higher likelihood of achieving the targets compared with the use of 3.0 mEq/l calcium dialysate. Conclusion: The severity of SHPT and the use of dialysate with higher calcium concentration are associated with practical difficulty in managing mineral metabolism in dialysis patients. Further prospective follow-up is needed to confirm our findings and to examine their impact on patient-level outcomes.

背景与研究目的：日本慢性肾脏病（CKD）5D期患者矿物质与骨异常转归研究（MBD-5D）是一项针对日本继发性甲状旁腺功能亢进（SHPT）血液透析患者的多中心前瞻性观察性研究。该国国内诊疗指南推荐的血清钙、血磷及全段甲状旁腺激素（PTH）控制目标分别为8.4~10.0 mg/dl、3.5~6.0 mg/dl及60~180 pg/ml。
研究方法：MBD-5D研究纳入接受血液透析时长超过3个月，且满足以下至少1项条件的受试者：全段甲状旁腺激素水平＞180 pg/ml，或接受静脉用维生素D受体激活剂（VDRAs）治疗，或口服维生素D受体激活剂类似物。本报告阐述了研究受试者的基线特征，并分析了与矿物质代谢达标相关的影响因素。
研究结果：全队列共从86家医疗机构纳入8229例患者，同时随机选取3276例患者作为亚队列。继发性甲状旁腺功能亢进的严重程度与达到血清钙、血磷目标值的可能性呈负相关；与未接受手术但甲状旁腺激素水平仍偏高的患者相比，有甲状旁腺切除术史的患者更易达成上述目标。与使用3.0 mEq/L钙透析液的患者相比，使用2.5 mEq/L钙透析液的患者达成目标的概率更高。
研究结论：继发性甲状旁腺功能亢进的严重程度以及使用高钙浓度透析液，与血液透析患者矿物质代谢管理的实际难度升高相关。未来需开展进一步的前瞻性随访研究以验证本研究结论，并分析其对患者个体临床转归的影响。