Malaguti Carla, Nery Luiz E, Dal Corso Simone, Nápolis Lara, De Fuccio Marcelo Bicalho, Castro Marise, Neder J Alberto
Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Division of Respiratory Diseases, Department of Medicine, Federal University of Sao Paulo (UNIFESP), São Paulo - Paulista School of Medicine, Brazil.
Eur J Appl Physiol. 2006 Nov;98(5):482-8. doi: 10.1007/s00421-006-0292-8. Epub 2006 Sep 21.
Skeletal muscle performance and muscle mass are commonly reduced in patients with advanced chronic obstructive pulmonary disease (COPD). It is currently unclear, however, whether negative changes in muscle structure and function are proportionately related to each other in these patients. In a cross-sectional study, 39 patients (post-bronchodilator FEV1=49.7+/-15.5% pred) and 17 controls were submitted to knee isokinetic dynamometry [peak torque (PT), isometric strength (IS), and total work (TW)] and dual energy X-ray absorptiometry for the evaluation of leg muscle mass (LMM). Muscle function (F) was normalised for LMM by using ratio standards (F.LMM-1), power function ratios (F.LMM-b, where b is usually not equal 1), and analysis of covariance (ANCOVA). Patients with COPD presented with reduced PT, IS, TW, and LMM as compared to controls: there were significant linear correlations among these variables in both groups (P<0.05). Ratio standards of PT.LMM-1 and TW.LMM-1 were, on average, 14% lower in patients than controls (P<0.01). The coefficients for allometric correction of IS and TW were significantly higher in patients as compared to controls (0.975 vs. 0.603 and 1.471 vs. 0.824, respectively, P<0.05), i.e. more LMM was needed to generate a given functional output in patients than normal subjects. In addition, adjusted means of muscle function variables by ANCOVA were 11-18% lower for patients than controls with LMM as the covariate (P<0.05). We conclude that factors other than simple atrophy (i.e. mass-independent mechanisms) might play a role in explaining the COPD-related skeletal muscle dysfunction.
晚期慢性阻塞性肺疾病（COPD）患者的骨骼肌性能和肌肉质量通常会降低。然而，目前尚不清楚这些患者肌肉结构和功能的负面变化是否彼此成比例相关。在一项横断面研究中，39例患者（支气管扩张剂后FEV1=49.7±15.5%预计值）和17名对照者接受了膝关节等速测力法（峰值扭矩（PT）、等长力量（IS）和总功（TW））以及双能X线吸收法以评估腿部肌肉质量（LMM）。通过使用比率标准（F.LMM-1）、幂函数比率（F.LMM-b，其中b通常不等于1）和协方差分析（ANCOVA）对LMM的肌肉功能（F）进行标准化。与对照组相比，COPD患者的PT、IS、TW和LMM降低：两组中这些变量之间均存在显著的线性相关性（P<0.05）。患者的PT.LMM-1和TW.LMM-1比率标准平均比对照组低14%（P<0.01）。与对照组相比，患者IS和TW的异速生长校正系数显著更高（分别为0.975对0.603和1.471对0.824，P<0.05），即与正常受试者相比，患者需要更多的LMM来产生给定的功能输出。此外，以LMM作为协变量，通过ANCOVA调整后的肌肉功能变量均值，患者比对照组低11%-18%（P<0.05）。我们得出结论，除了单纯萎缩之外的因素（即与质量无关的机制）可能在解释COPD相关的骨骼肌功能障碍中起作用。
