Department of Physical Therapy, Human Health Sciences, Graduate School of Medicine, Kyoto University, 53-Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan.
Department of Healthcare Epidemiology, School of Public Health in the Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Clin Rheumatol. 2021 Jul;40(7):2889-2896. doi: 10.1007/s10067-021-05591-0. Epub 2021 Jan 23.
INTRODUCTION/OBJECTIVES: To test the hypothesis that greater extracellular-to-intracellular water (ECW/ICW) ratios in lower-limb muscles are associated with worsened functional abilities in patients with knee osteoarthritis (OA).
We analyzed data from 787 participants (82.2% female; mean age, 69.6 ± 5.3 years) from the Nagahama Prospective Cohort who were ≥60 years old and had radiographically confirmed bilateral knee OA. The Knee Scoring System (KSS) was used to assess functional abilities. Lower-limb ECW/ICW ratios and skeletal mass index values were determined with multi-frequency bioelectrical impedance analysis (BIA). Multiple linear regression analysis was used to test for associations between ECW/ICW ratios and functional abilities. Subgroup analyses based on OA severities and symptomaticity were also conducted.
Increased ECW/ICW ratios were associated with a 4.38-point decrease in the KSS function scores (95% confidence interval [CI], 3.15-5.62 points) after adjusting for covariates. This association varied according to the degree of knee symptoms, especially in individuals with radiologically mild OA. ECW/ICW ratios in individuals with asymptomatic mild OA were associated with a 2.14-point decrease in the KSS function score (95% CI, 0.32-3.96 points), whereas those in individuals with severe symptomatic mild OA were associated with a 6.16-point decrease (95% CI, 2.13-10.19 points).
Our findings indicate that higher ECW/ICW ratios are associated with greater functional disability in patients with knee OA. Therefore, ECW/ICW ratio measurements with multi-frequency BIA can serve as valuable indicators for functional disability in patients with knee OA. Key Points • Higher extracellular-to-intracellular water (ECW/ICW) ratios are associated with greater functional disability levels in patients with knee osteoarthritis (OA). • ECW/ICW ratios are useful clinical signs as a biomarker for poor functional abilities in patients with knee OA.
简介/目的：测试以下假设，即下肢肌肉中外细胞水（ECW/ICW）比例的增加与膝骨关节炎（OA）患者功能能力的恶化有关。
我们分析了来自日本长滨前瞻性队列的 787 名参与者（82.2%为女性；平均年龄 69.6±5.3 岁）的数据，这些参与者年龄均≥60 岁且双侧膝关节 OA 经放射学确诊。使用膝关节评分系统（KSS）评估功能能力。通过多频生物电阻抗分析（BIA）测定下肢 ECW/ICW 比值和骨骼质量指数值。使用多元线性回归分析来检验 ECW/ICW 比值与功能能力之间的关联。还根据 OA 严重程度和症状性进行了亚组分析。
调整协变量后，ECW/ICW 比值增加与 KSS 功能评分降低 4.38 分（95%置信区间[CI]，3.15-5.62 分）相关。这种关联根据膝关节症状的严重程度而有所不同，特别是在影像学轻度 OA 患者中。无症状轻度 OA 患者的 ECW/ICW 比值与 KSS 功能评分降低 2.14 分（95%CI，0.32-3.96 分）相关，而严重症状性轻度 OA 患者的 ECW/ICW 比值与 KSS 功能评分降低 6.16 分（95%CI，2.13-10.19 分）相关。
我们的研究结果表明，较高的 ECW/ICW 比值与膝 OA 患者的功能障碍程度增加有关。因此，多频 BIA 的 ECW/ICW 比值测量可作为膝 OA 患者功能障碍的有价值指标。关键点 • 较高的细胞外-细胞内水（ECW/ICW）比值与膝骨关节炎（OA）患者的功能障碍水平升高相关。• ECW/ICW 比值是作为膝 OA 患者功能能力不良的生物标志物的有用临床指标。
