We identified the strength cutpoints concerning mobility impairment, then identified the muscle mass cutpoints concerning weakness, and compared the results with other diagnostic criteria to develop the clinical diagnostic criteria associated with functional impairment. In 7583 elderly people, classification and regression tree (CART) and receiver operating characteristic curve (ROC) analyses were used for determining cutpoints for handgrip strength (HGS) and appendicular lean mass (ALM) indices associated with slowness or weakness. Logistic regressions were then used to quantify the strength of the association between muscle mass (or strength) categories and weakness (or slowness). The CART second cutpoints of muscle mass and strength indices were lower than those specified by the ROC method and were between those cutpoints determined by the 20th and Mean-2SD methods. After adjusting for covariates, the associations remained significant in handgrip strength categories defined by the CART and ROC cutpoints and HGS/BMI categories defined by the CART, ROC, and 20th cutpoints in men and women (P < 0.05), ALM, ALM/Ht² categories defined by all four cutpoints (P < 0.05) and ALM/BMI categories defined by CART and ROC cutpoints in men (P < 0.05), and ALM and ALM/Ht² categories defined by the CART cutpoints in women (P < 0.05). Our approaches resulted in a definition of weak strength as handgrip strength or HGS/BMI less than 26.55 kg or 1.114 in men and less than 16.45 kg or 0.697 in women and then defined ALM, ALM/Ht², or ALM/BMI less than 18.92 kg, 7.08 kg/m², or 0.795 in men and less than 15.04 kg, 5.99 kg/m², or 0.517 in women as low lean mass.

我们确定了与活动障碍有关的力量分界点，然后确定了与无力有关的肌肉质量分界点，并将结果与​​其他诊断标准进行了比较，以制定与功能障碍相关的临床诊断标准。在 7583 名老年人中，分类和回归树 (CART) 和受试者工作特征曲线 (ROC) 分析用于确定与缓慢或无力相关的握力 (HGS) 和附肢瘦体重 (ALM) 指数的切点。然后使用逻辑回归来量化肌肉质量（或力量）类别与虚弱（或缓慢）之间关联的强度。肌肉质量和力量指数的 CART 第二个分界点低于 ROC 方法指定的那些分界点，并且介于 20th 和 Mean-2SD 方法确定的分界点之间。在对协变量进行调整后，在由 CART 和 ROC 分界点定义的握力类别以及由 CART、ROC 和第 20 个分界点定义的男性和女性的 HGS/BMI 类别中，这些关联仍然显着。P  < 0.05)、ALM、ALM/Ht ²类别由所有四个分界点定义 ( P  < 0.05) 和 ALM/BMI 类别由男性 CART 和 ROC 分界点定义 ( P  < 0.05)，以及 ALM 和 ALM/Ht ²类别定义通过女性的 CART 切点（P  < 0.05）。我们的方法将弱力量定义为男性握力或 HGS/BMI 小于 26.55 kg 或 1.114，女性小于 16.45 kg 或 0.697，然后定义 ALM、ALM/Ht ²或 ALM/BMI 小于 18.92 kg、7.08 kg/m ²或 0.795（男性）和小于 15.04 kg、5.99 kg/m ²或 0.517（女性）为低瘦体重。