Universidade Nove de Julho, São Paulo, SP, Brasil.
Universidade de São Paulo, Faculdade de Medicina, Hospital das Clínicas, São Paulo, SP, Brasil.
J Bras Nefrol. 2021 Apr-Jun;43(2):269-273. doi: 10.1590/2175-8239-JBN-2020-0063.
Body composition is critical for the evaluation of patients with Chronic Kidney Disease (CKD) and can be obtained from either multifrequency bioelectrical impedance analysis (BIA) or dual-energy absorptiometry (DXA). Although the discrepancy between the results obtained from both methods has already been described, reasons are unknown, and might be related to secondary hyperparathyroidism, which is associated with bone loss.
We have evaluated 49 patients (25 males and 24 females): 20 with CKD not on dialysis and 29 on maintenance hemodialysis [18 with severe hyperparathyroidism (HD-SHPT) and 11 submitted to parathyroidectomy (HD-PTX)]. All patients underwent DXA and BIA.
The median age and body mass index (BMI) were 49 years and 25.6 kg/m2, respectively. Patients exhibited low bone mineral content (BMC) measured by DXA, particularly those from the HD-SHPT group. The largest BMC measurement disagreement between DXA and BIA was found in the HD-SHPT group (p=0.004). Factors independently associated with this discrepancy in BMC measurement were serum phosphate (p=0.003) and patient group (p=0.027), even after adjustments for age, BMI, and gender (adjusted r2=0.186). PTX attenuated this difference.
BIA should be interpreted with caution in patients with SHPT due to a loss of accuracy, which can compromise the interpretation of body composition.
人体成分对于慢性肾脏病（CKD）患者的评估至关重要，可以通过多频生物电阻抗分析（BIA）或双能吸收法（DXA）获得。尽管这两种方法的结果已经存在差异，但原因尚不清楚，可能与继发性甲状旁腺功能亢进症有关，后者与骨丢失有关。
我们评估了 49 名患者（25 名男性和 24 名女性）：20 名未接受透析的 CKD 患者和 29 名维持性血液透析患者[18 名严重甲状旁腺功能亢进（HD-SHPT）和 11 名甲状旁腺切除术（HD-PTX）]。所有患者均接受了 DXA 和 BIA 检查。
患者的中位年龄和体重指数（BMI）分别为 49 岁和 25.6kg/m2。DXA 测量的患者骨矿物质含量（BMC）较低，尤其是 HD-SHPT 组。DXA 和 BIA 之间 BMC 测量差异最大的是 HD-SHPT 组（p=0.004）。与 BMC 测量差异相关的独立因素是血清磷酸盐（p=0.003）和患者组（p=0.027），即使在调整年龄、BMI 和性别后（调整 r2=0.186）。PTX 减轻了这种差异。
由于准确性降低，SHPT 患者 BIA 的解释应谨慎，这可能会影响身体成分的解释。
