OBJECTIVE To assess the value of electrical impedance myography (EIM) in inclusion body myositis (IBM). METHODS Patients with clinically defined IBM and healthy controls (HC) of similar age group were recruited. Each participant underwent manual muscle testing (MMT), 6-min walk test (6MWT), handgrip dynamometry, and IBM-functional rating scale assessment (IBM-FRS). EIM measurements were obtained from bilateral deltoid, biceps, forearm-flexors, quadriceps, tibialis anterior, and medial gastrocnemius. RESULTS Fourteen IBM patients and 12 HCs with mean age 68.6 ± 6 and 67.4 ± 5.4 years were included in the final analysis. Averaged phase value at 50 kHz (EIM50) and ratio of phase value at 50 kHz/200 kHz (EIMPR) from six-muscles were significantly lower in IBM patients when compared to HC (5.23 ± 1.34 vs 7.88 ± 1.9, p-value 0.002, and 0.55 ± 0.09 vs. 0.68 ± 0.09, p-value 0.004, respectively). A strong correlation was noted between IBM-FRS, 6MWT, disease-duration and the averaged value of EIM50 and EIMPR in the IBM patients (Spearman |rho|>0.7, p-values < 0.01). CONCLUSIONS EIM can differentiate between IBM patients and HCs and EIM parameters correlate with clinical outcome measures. SIGNIFICANCE EIM may be a potential objective biomarker for IBM. A longitudinal validation study is warranted.

中文翻译：

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电阻抗肌电图作为包涵体肌炎的生物标志物：横断面研究

目的 评估电阻抗肌电图（EIM）在包涵体肌炎（IBM）中的价值。方法 招募具有临床定义的 IBM 和相似年龄组的健康对照 (HC) 的患者。每个参与者都接受了手动肌肉测试 (MMT)、6 分钟步行测试 (6MWT)、握力测量和 IBM 功能评定量表评估 (IBM-FRS)。EIM 测量值来自双侧三角肌、二头肌、前臂屈肌、股四头肌、胫前肌和腓肠肌内侧。结果 最终分析包括 14 名 IBM 患者和 12 名 HC，平均年龄分别为 68.6 ± 6 和 67.4 ± 5.4 岁。与 HC 相比，IBM 患者 50 kHz 的平均相位值 (EIM50) 和 50 kHz/200 kHz 的相位值比 (EIMPR) 的六块肌肉显着低于 HC（5.23 ± 1.34 vs 7.88 ± 1.9，p 值 0.002 , 和 0.55 ± 0.09 对 0。68 ± 0.09，p 值分别为 0.004）。IBM-FRS、6MWT、疾病持续时间与 IBM 患者的 EIM50 和 EIMPR 的平均值之间存在很强的相关性（Spearman |rho|>0.7，p 值 < 0.01）。结论 EIM 可以区分 IBM 患者和 HC，并且 EIM 参数与临床结果测量相关。意义 EIM 可能是 IBM 的一个潜在的客观生物标志物。有必要进行纵向验证研究。