Bone and mineral metabolism abnormalities are frequent in kidney transplant recipients and have been associated with cardiovascular morbidity. The primary aim of this study was to analyse the association between routine clinically available biochemical evaluation, non-routine histomorphometric bone evaluation, and vascular disease in kidney transplanted patients. A cross-sectional analysis was performed on 69 patients, 1-year after kidney transplantation. Laboratory analysis, radiography of hands and pelvis, bone biopsy, bone densitometry, and coronary CT were performed. One-year post-transplantation, nearly one-third of the patients presented with hypercalcemia, 16% had hypophosphatemia, 39.3% had iPTH levels > 150 pg/mL, 20.3% had BALP levels > 40 U/L, and 26.1% had hypovitaminosis D. Evaluation of extraosseous calcifications revealed low Adragão and Agatston scores. We divided patients into three clusters, according to laboratory results routinely used in clinical practice: hypercalcemia and hyperparathyroidism (Cluster1); hypercalcemia and high BALP levels (Cluster2); hypophosphatemia and vitamin D deficiency (Cluster 3). Patients in clusters 1 and 2 had higher cortical porosity (p = 0.001) and osteoid measurements, although there was no difference in the presence of abnormal mineralization, or low volume. Patients in cluster 2 had a higher BFR/BS (half of the patients in cluster 2 had high bone turnover), and most patients in cluster 1 had low or normal bone turnover. Cluster 3 has no differences in volume, or turnover, but 60% of the patients presented with pre-osteomalacia. All three clusters were associated with high vascular calcifications scores. Vascular calcifications scores were not related to higher bone mineral density. Instead, an association was found between a higher Adragão score and the presence of osteoporosis at the femoral neck (p = 0.008). In conclusion, inferring bone TMV by daily clinical biochemical analysis can be misleading, and bone biopsy is important for assessing both bone turnover and mineralization after kidney transplantation, although hypophosphatemia combined with vitamin D deficiency is associated with abnormal mineralization. The presence of hypercalcemia with high levels of PTH or high levels of BALP, or hypophosphatemia and vitamin D deficiency should remind us to screen vascular calcification status of patients.

Clinical Research: ClinicalTrials.gov ID NCT02751099.

骨和矿物质代谢异常在肾移植受者中很常见，并且与心血管发病率相关。本研究的主要目的是分析肾移植患者常规临床生化评估、非常规骨组织形态学评估与血管疾病之间的关联。对肾移植 1 年后的 69 名患者进行了横断面分析。进行了实验室分析、手部和骨盆的X光检查、骨活检、骨密度测定和冠状动脉CT。移植后一年，近三分之一的患者出现高钙血症，16% 出现低磷血症，39.3% 的 iPTH 水平 > 150 pg/mL，20.3% 的 BALP 水平 > 40 U/L，26.1% 的维生素缺乏症D. 骨外钙化的评估显示 Adragão 和 Agatston 评分较低。根据临床实践中常规使用的实验室结果，我们将患者分为三组：高钙血症和甲状旁腺功能亢进（Cluster1）；高钙血症和高 BALP 水平（Cluster2）；低磷血症和维生素 D 缺乏（第 3 类）。第 1 组和第 2 组中的患者具有较高的皮质孔隙度 ( p  = 0.001) 和骨样测量值，但异常矿化或低体积的存在没有差异。第 2 组中的患者具有较高的 BFR/BS（第 2 组中一半的患者骨转换较高），而第 1 组中的大多数患者骨转换较低或正常。第 3 组的体积或周转率没有差异，但 60% 的患者出现骨软化​​前期症状。所有三个簇都与高血管钙化评分相关。血管钙化评分与较高的骨密度无关。相反，较高的 Adragão 评分与股骨颈骨质疏松症之间存在关联 ( p  = 0.008)。总之，通过日常临床生化分析推断骨 TMV 可能会产生误导，骨活检对于评估肾移植后骨转换和矿化非常重要，尽管低磷血症合并维生素 D 缺乏与异常矿化有关。存在高钙血症伴高水平PTH或高水平BALP，或低磷血症和维生素D缺乏应提醒我们筛查患者的血管钙化状态。

临床研究：ClinicalTrials.gov ID NCT02751099。