UOC di Nutrizione Clinica, Dipartimento di Scienze Gastroenterologiche, Endocrino-Metaboliche e Nefro-Urologiche, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; Istituto di Patologia Speciale Medica, Università Cattolica del Sacro Cuore, Rome, Italy.
UOC di Neurologia, Dipartimento di Scienze dell'Invecchiamento, Neurologiche, Ortopediche e della Testa-Collo; Istituto di Neurologia, Università Cattolica del Sacro Cuore, Rome, Italy.
Nutrition. 2019 Nov-Dec;67-68:110546. doi: 10.1016/j.nut.2019.05.012. Epub 2019 Jul 2.
Myotonic dystrophy type 1 (DM1) is an inherited muscle disorder characterized by slowly progressive weakness due to muscle degeneration. The Muscular Impairment Rating Scale (MIRS) is validated to assess clinical muscle severity of patients with DM1, although the scale is not sensitive enough to assess disease progression in time intervals fit for clinical trials. The aim of this study was to analyze bioelectrical whole body and arm segmental parameters in patients with DM1 to explore a correlation between bioelectrical impedance analysis (BIA) parameters and disease stage.
Forty patients with DM1 were enrolled in a cross-sectional study. In all patients, MIRS, handgrip strength (HGS), and BIA were assessed. A Kruskal-Wallis test was used to assess the difference in continuous variables according to MIRS. Correlation between BIA values and HGS were made by Pearson's coefficient analysis. A linear regression analysis was performed.
Eighteen of 40 patients were men (45%). The median age of the cohort was 42 y (30-58 y). Four patients (10%) were classified as MIRS 1; 20 (50%) MIRS 2; 11 (27.5%) MIRS 3; and 5 (12.5%) as MIRS 4. A correlation was observed between phase angle and MIRS (P = 0.0001). MIRS correlated with other BIA values such as resistance, impedance ratio, and capacitance (P = 0.005, P = 0.0001, P = 0.0006, respectively). At linear regression analysis, segmental resistance, phase angle, impedance ratio, and capacitance of both arms significantly correlated with HGS.
Results from the study support the use of BIA as a suitable procedure for staging DM1 muscle involvement and as a measure of muscle disease outcome, in clinical practice and in clinical trial design of therapeutic drugs.
1 型肌强直性营养不良（DM1）是一种遗传性肌肉疾病，其特征为肌肉退化导致的进行性肌无力。肌肉损伤评分量表（MIRS）已被验证可用于评估 DM1 患者的临床肌肉严重程度，但该量表不够敏感，无法及时评估适合临床试验的疾病进展情况。本研究旨在分析 DM1 患者的全身生物电阻抗和手臂节段参数，以探讨生物电阻抗分析（BIA）参数与疾病阶段之间的相关性。
本研究共纳入 40 例 DM1 患者，进行了横断面研究。对所有患者进行 MIRS、握力（HGS）和 BIA 评估。采用 Kruskal-Wallis 检验根据 MIRS 评估连续变量的差异。通过 Pearson 系数分析评估 BIA 值与 HGS 之间的相关性。进行线性回归分析。
40 例患者中 18 例（45%）为男性。队列的中位年龄为 42 岁（30-58 岁）。4 例（10%）患者为 MIRS 1 级；20 例（50%）为 MIRS 2 级；11 例（27.5%）为 MIRS 3 级；5 例（12.5%）为 MIRS 4 级。相位角与 MIRS 之间存在相关性（P=0.0001）。MIRS 与其他 BIA 值（如电阻、阻抗比和电容）相关（P=0.005、P=0.0001、P=0.0006）。线性回归分析显示，双臂节段电阻、相位角、阻抗比和电容与 HGS 显著相关。
本研究结果支持将 BIA 作为 DM1 肌肉受累分期的一种合适方法，以及在临床实践和治疗药物临床试验设计中评估肌肉疾病结局的一种方法。
