Kittiskulnam Piyawan, Chertow Glenn M, Carrero Juan J, Delgado Cynthia, Kaysen George A, Johansen Kirsten L
Division of Nephrology, University of California San Francisco and San Francisco VA Medical Center, San Francisco, California, USA; Division of Nephrology, Department of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand.
Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.
Kidney Int. 2017 Jul;92(1):238-247. doi: 10.1016/j.kint.2017.01.024. Epub 2017 Mar 17.
The relative importance of sarcopenia and its individual components as independent predictors of mortality in the dialysis population has not been determined. We estimated whole-body muscle mass using pre-dialysis bioimpedance spectroscopy measurements in 645 ACTIVE/ADIPOSE-enrolled prevalent hemodialysis patients from San Francisco and Atlanta. Low muscle mass was defined as two standard deviations below sex-specific means for young adults from NHANES and indexed to height, body weight, body surface area, or body mass index. We evaluated the association of sarcopenia (low muscle mass) by four indexing methods, weak hand grip strength, and slow gait speed with mortality. Seventy-eight deaths were observed during a mean follow-up of 1.9 years. Sarcopenia was not significantly associated with mortality after adjusting for covariates. No muscle mass criteria were associated with death, regardless of indexing metrics. In contrast, having weak grip strength or slow walking speed was associated with mortality in the adjusted model. Only gait slowness significantly improved the predictive accuracy for death with an increase in C-statistic from 0.63 to 0.68. However, both gait slowness and hand grip weakness significantly improved the net reclassification index compared to models without performance measures (50.5% for slowness and 33.7% for weakness), whereas models with muscle size did not. Neither sarcopenia nor low muscle mass by itself was a better predictor of mortality than functional limitation alone in patients receiving hemodialysis. Thus, physical performance measures, including slow gait speed and weak hand grip strength, were associated with mortality even after adjustment for muscle size and other confounders.
在透析人群中，肌肉减少症及其各个组成部分作为死亡率独立预测因素的相对重要性尚未确定。我们使用透析前生物电阻抗光谱测量法，对来自旧金山和亚特兰大的645名参加ACTIVE/ADIPOSE研究的血液透析患者的全身肌肉质量进行了评估。低肌肉质量被定义为比来自美国国家健康与营养检查调查（NHANES）的年轻成年人按性别划分的均值低两个标准差，并根据身高、体重、体表面积或体重指数进行指数化。我们通过四种指数化方法、弱握力和慢步速来评估肌肉减少症（低肌肉质量）与死亡率之间的关联。在平均1.9年的随访期间观察到78例死亡。在对协变量进行调整后，肌肉减少症与死亡率无显著关联。无论采用何种指数化指标，没有任何肌肉质量标准与死亡相关。相比之下，在调整后的模型中，握力弱或步速慢与死亡率相关。只有步速慢显著提高了死亡预测准确性，C统计量从0.63增加到0.68。然而，与没有性能指标的模型相比，步速慢和握力弱都显著提高了净重新分类指数（步速慢为50.5%，握力弱为33.7%），而包含肌肉大小的模型则没有。在接受血液透析的患者中，肌肉减少症或低肌肉质量本身都不是比单纯功能受限更好的死亡率预测指标。因此，即使在对肌肉大小和其他混杂因素进行调整后，包括步速慢和握力弱在内的身体性能指标仍与死亡率相关。
