Department of Internal Medicine 1, Shimane University Faculty of Medicine, Shimane, Japan.
Nephron Clin Pract. 2010;115(1):c51-8. doi: 10.1159/000286350. Epub 2010 Feb 19.
BACKGROUND/AIMS: Serum parathyroid hormone (PTH) concentration provides a rough index of the severity of secondary hyperparathyroidism (SHPT) due to chronic renal failure. Since serum PTH inversely related to calcium (Ca) level, we attempted to create a new index based on the relationship.
Our subjects were 70 patients undergoing maintenance hemodialysis (HD) in a single facility. Using multiple pairs of serum Ca corrected for albumin (cCa) and intact PTH (iPTH) values drawn simultaneously, we determined the steepest slope of cCa-iPTH relationship for each individual patient to get a line closely resembling the cCa-PTH sigmoidal curve.
Based on the slopes, the following equation was obtained: iPTH2 = iPTH1 + (cCa1 - cCa2) x (43 + 0.47 x iPTH1), where the PTH values at any 2 arbitrary values of cCa1 and cCa2 were assumed to be iPTH1 and iPTH2, respectively. When 'corrected PTH' is defined as the predicted value of iPTH at cCa = 9.0 mg/dl, its correlation was better than iPTH with the total volume of the parathyroid glands estimated by ultrasonography. Similar results were found in 30 parathyroidectomized patients at other facilities.
'Corrected PTH' may represent a useful parameter for assessing the severity of SHPT from single determinations of cCa and iPTH drawn at the same time.
背景/目的：血清甲状旁腺激素 (PTH) 浓度为慢性肾衰竭引起的继发性甲状旁腺功能亢进症 (SHPT) 的严重程度提供了一个粗略的指标。由于血清 PTH 与钙 (Ca) 水平呈反比，我们试图基于这种关系创建一个新的指标。
我们的研究对象是在一个机构接受维持性血液透析 (HD) 的 70 名患者。通过同时绘制多个血清 Ca 校正白蛋白 (cCa) 和完整 PTH (iPTH) 值的配对，我们确定了每个个体患者的 cCa-iPTH 关系的最陡斜率，以获得一条与 cCa-PTH 曲线相似的线。
根据斜率，得到以下方程：iPTH2 = iPTH1 + (cCa1 - cCa2) x (43 + 0.47 x iPTH1)，其中 cCa1 和 cCa2 处的任意 2 个 PTH 值分别假设为 iPTH1 和 iPTH2。当“校正后 PTH”定义为 cCa = 9.0 mg/dl 时的 iPTH 预测值时，它与超声检查估计的甲状旁腺总体积的相关性优于 iPTH。在其他机构的 30 名甲状旁腺切除术患者中也发现了类似的结果。
“校正后 PTH”可能是一种有用的参数，可用于评估从同一时间同时绘制的 cCa 和 iPTH 单次测定中评估 SHPT 的严重程度。
