Leicester Kidney Lifestyle Team, Department of Health Sciences, University of Leicester, Leicester, UK.
NIHR Leicester Biomedical Research Centre, Leicester, UK.
Nephrology (Carlton). 2020 Jun;25(6):467-474. doi: 10.1111/nep.13678. Epub 2019 Nov 22.
Patients with chronic kidney disease (CKD) are characterised by low skeletal muscle mass that negatively impacts physical performance. Operational definitions of 'low muscle mass' are inconsistent, and it is unknown how different skeletal muscle mass indices affect the relationship between muscle mass and physical function.
Appendicular skeletal muscle mass (ASM) was measured by dual-energy X-ray absorptiometry in 72 CKD patients. Along with crude ASM, alternative muscle indices were calculated adjusting for height, height-squared, body mass, and BMI. Physical performance was assessed by handgrip strength, sit-to-stand tests, gait speed, the incremental shuttle walk test and 'Short Physical Performance Battery'.
Prevalence of 'low muscle mass' ranged from 26% to 35% of patients depending on the criteria used. The relationship between muscle mass indices and physical function differed for each criteria. Using average coefficients, the association with overall physical function and muscle indices were as follows: crude ASM (r = .258), ASM/height (r = .249), ASM/height-squared (r = .332), ASM/body mass (r = .249) and ASM/BMI (r = .206). Muscle adjusted for markers of adiposity (ASM/body fat %, r = .266; ASM/fat mass, r = .338) provided the best overall associations with physical function.
The use of alternative muscle mass indices provide different estimates of 'low muscle mass' prevalence, and the strongest (and most useful definition in regard to functional status) involves adjustment for either total or relative body fat. ASM adjusted for adiposity may be physiologically and clinically more relevant in patients with renal disease.
患有慢性肾脏病（CKD）的患者通常具有较低的骨骼肌质量，这会对身体机能产生负面影响。“肌肉量低”的操作定义并不一致，并且尚不清楚不同的骨骼肌质量指数如何影响肌肉量与身体功能之间的关系。
通过双能 X 射线吸收法在 72 例 CKD 患者中测量四肢骨骼肌质量（ASM）。除了 ASM 的原始值外，还通过身高、身高平方、体重和 BMI 进行调整，计算出其他肌肉指数。通过握力、坐站测试、步态速度、递增式穿梭步行测试和“简短身体机能测试”来评估身体机能。
根据所使用的标准，“肌肉量低”的患病率在 26％至 35％的患者之间不等。肌肉质量指数与身体功能之间的关系因每种标准而异。使用平均系数，肌肉质量指数与整体身体功能的关联如下：原始 ASM（r =.258）、ASM/身高（r =.249）、ASM/身高平方（r =.332）、ASM/体重（r =.249）和 ASM/体重指数（r =.206）。肌肉质量与体脂标志物（ASM/体脂肪百分比，r =.266；ASM/脂肪质量，r =.338）进行调整可提供与身体功能的最佳总体关联。
使用替代的肌肉质量指数可以提供“肌肉量低”患病率的不同估计值，而最强（且与功能状态最相关）的定义是对总体或相对体脂肪进行调整。对肥胖进行调整的 ASM 可能在患有肾脏疾病的患者中具有生理和临床相关性。
