Abdalbary M, Chishti E, Shakhashiro M, Mohamed R, Parikh T, Nassar M K, Sayed-Ahmed N, Faugere M-C, Sawaya B P, El-Husseini A
Mansoura Nephrology and Dialysis Unit, Mansoura University, 1 El Gomhouria St, Mansoura, Dakahlia Governorate, 35516, Egypt.
Division of Nephrology & Bone and Mineral Metabolism, University of Kentucky, Lexington, USA.
Osteoporos Int. 2023 Apr;34(4):763-774. doi: 10.1007/s00198-023-06686-x. Epub 2023 Feb 15.
The impact of urine calcium on kidney, bone, and cardiovascular systems in osteoporosis is not well-known. In this 7-year-follow-up study, high urine calcium did not affect kidney function but increased risk of kidney stones, while low urine calcium increased cardiovascular diseases. Maintaining normal urine calcium is beneficial for bone health.
Hypercalciuria is common in patients with osteoporosis. However, the long-term effect of urinary calcium excretion (UCaE) on patients' health is not well-examined. The current study aims to assess the impact of UCaE on kidney, bone, and cardiovascular outcomes in patients with bone biopsy proven osteoporosis.
Longitudinal study of all patients with osteoporosis who underwent bone biopsy and 24-h urine collection between 2008 and 2015 in the University of Kentucky. DXA scans, serum markers, kidney function, and cardiovascular events were recorded until last clinic visit in 2021. Exclusion criteria were secondary osteoporosis or conditions that might substantially impact UCaE. The significant results in univariate analysis were confirmed in multi-variable regression models involving clinically important covariates that might impact patients' outcomes.
Study included 230 patients with mean follow-up of 7.2 ± 2.9 years. The mean age was 61 years, and the mean eGFR at baseline was 85 ± 19 ml/min/1.73 m. Low bone turnover (LBT) was present in 57% and high bone turnover (HBT) in 43% of patients. Hypercalciuria was found in one-third of patients with no difference between LTB and HTB. UCaE correlated positively with eGFR but did not affect the rate of eGFR decline over time. Higher UCaE predicted kidney stones development. We observed U-shaped effect of UCaE on bone health. Hypercalciuria predicted loss of BMD at all sites, but also hypocalciuria was associated with higher loss in total hip BMD. Upper limb fractures were the most observed fractures, and their incidence was higher in patients with hyper- or hypo-calciuria. Lower UCaE independently predicted development of major adverse cardiac events (MACE) and cardiovascular disease (CVD).
UCaE correlated with eGFR but it did not affect the change of eGFR over time. Patients with normal UCaE had lower incidence of upper limb fractures and less reduction in BMD. Low UCaE predicted MACE and CVD.
尿钙对骨质疏松症患者肾脏、骨骼和心血管系统的影响尚不清楚。在这项为期7年的随访研究中，高尿钙不影响肾功能，但会增加肾结石风险，而低尿钙则会增加心血管疾病风险。维持正常尿钙对骨骼健康有益。
高钙尿症在骨质疏松症患者中很常见。然而，尿钙排泄（UCaE）对患者健康的长期影响尚未得到充分研究。本研究旨在评估UCaE对经骨活检证实为骨质疏松症患者的肾脏、骨骼和心血管结局的影响。
对2008年至2015年期间在肯塔基大学接受骨活检和24小时尿液收集的所有骨质疏松症患者进行纵向研究。记录双能X线吸收测定（DXA）扫描、血清标志物、肾功能和心血管事件，直至2021年最后一次门诊就诊。排除标准为继发性骨质疏松症或可能显著影响UCaE的疾病。单变量分析中的显著结果在涉及可能影响患者结局的临床重要协变量的多变量回归模型中得到证实。
研究纳入230例患者，平均随访7.2±2.9年。平均年龄为61岁，基线时平均估算肾小球滤过率（eGFR）为85±19 ml/min/1.73 m²。57%的患者存在低骨转换（LBT），43%的患者存在高骨转换（HBT）。三分之一的患者存在高钙尿症，LTB和HTB患者之间无差异。UCaE与eGFR呈正相关，但不影响eGFR随时间的下降速率。较高的UCaE可预测肾结石的发生。我们观察到UCaE对骨骼健康呈U形影响。高钙尿症可预测所有部位骨密度（BMD）的丢失，但低钙尿症也与全髋BMD的更高丢失相关。上肢骨折是最常见的骨折类型，高钙尿症或低钙尿症患者的骨折发生率更高。较低的UCaE独立预测主要不良心脏事件（MACE）和心血管疾病（CVD）的发生。
UCaE与eGFR相关，但不影响eGFR随时间的变化。尿钙正常的患者上肢骨折发生率较低，BMD降低较少。低UCaE可预测MACE和CVD。
