Department of Urology, Osaka Metropolitan University Graduate School of Medicine, 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan.
Innovative and Clinical Research Promotion Center, Gifu University Hospital, 1-1, Yanagido, Gifu, 501-1194, Japan.
Clin Nutr. 2022 Sep;41(9):1881-1888. doi: 10.1016/j.clnu.2022.07.028. Epub 2022 Jul 31.
BACKGROUND & AIMS: Skeletal muscle mass decreases in patients with chronic kidney disease, especially those on dialysis with end-stage kidney disease. On the other hand, the recovery of renal function due to successful kidney transplantation (KT) improves skeletal muscle mass loss. However, low protein intake may influence the changes in skeletal muscle mass after KT. The aim of the present study is to examine the association of the changes in skeletal muscle mass with protein intake in kidney transplant recipients (KTRs).
A cohort study was conducted in KTRs and living-kidney donors (LKDs). Skeletal muscle mass index (SMI) was measured using bioelectrical impedance analysis before KT and at 1 month and 12 months after KT. Protein intake was calculated with 24-h urine urea nitrogen from the Maroni formula at 12 months after KT. To evaluate the association between protein intake and the changes in SMI during the first year after KT, we performed a multivariable regression analysis adjusted for covariates including age, sex, cumulative glucocorticoids, cumulative hospitalization, diabetes mellitus, and SMI before KT.
In KTRs (n = 64), the median SMI was 7.26 kg/m before KT, which decreased to 7.01 kg/m at 1 month after KT and increased to 7.55 kg/m at 12 months after KT. In LKDs (n = 17), the median SMI was 6.24 kg/m before KT which increased to 6.40 kg/m at 1 month after KT and further increased to 6.95 kg/m at 12 months after KT. The changes in SMI during the 1-year period after KT exhibited a positive correlation with protein intake (p = 0.015) after adjustment. The predicted value of protein intake in KTRs, whose values of SMI before KT and at 12 months after KT were the same, was 0.72 g/kg ideal body weight (IBW)/day using the multivariable non-linear regression model.
In KTRs, insufficient protein intake adversely affected the recovery from skeletal muscle mass loss after KT. Therefore, a protein intake of at least more than 0.72 g/kg IBW/day, the predicted value obtained in the present study, might be recommended for KTRs suffering from skeletal muscle mass loss.
慢性肾脏病患者的骨骼肌量减少，尤其是接受终末期肾病透析的患者。另一方面，由于成功的肾移植（KT）而恢复的肾功能可改善骨骼肌量的丢失。然而，低蛋白摄入可能会影响 KT 后骨骼肌量的变化。本研究旨在探讨 KT 后骨骼肌量变化与蛋白摄入的关系。
本研究进行了一项 KT 受者（KTR）和活体供肾者（LKD）的队列研究。在 KT 前、 KT 后 1 个月和 12 个月使用生物电阻抗分析测量骨骼肌质量指数（SMI）。在 KT 后 12 个月，通过 Maroni 公式的 24 小时尿尿素氮计算蛋白摄入量。为了评估 KT 后 1 年内蛋白摄入与 SMI 变化之间的关系，我们进行了多变量回归分析，调整了年龄、性别、累积糖皮质激素、累积住院、糖尿病和 KT 前 SMI 等混杂因素。
在 KTR 组（n=64）中， KT 前 SMI 的中位数为 7.26kg/m2， KT 后 1 个月时降至 7.01kg/m2， KT 后 12 个月时增至 7.55kg/m2。在 LKD 组（n=17）中， KT 前 SMI 的中位数为 6.24kg/m2， KT 后 1 个月时增至 6.40kg/m2， KT 后 12 个月时进一步增至 6.95kg/m2。KT 后 1 年内 SMI 的变化与蛋白摄入呈正相关（p=0.015），经调整后。在 KTR 组中，根据多变量非线性回归模型，当 KT 前和 KT 后 12 个月的 SMI 值相同时，预测值为 0.72g/kg 理想体重（IBW）/天。
在 KTR 中，蛋白摄入不足会对 KT 后骨骼肌量恢复产生不利影响。因此，建议 KTR 摄入至少 0.72g/kg IBW/day 的蛋白，这是本研究中得出的预测值。
