Maddocks Matthew, Shrikrishna Dinesh, Vitoriano Simone, Natanek Samantha A, Tanner Rebecca J, Hart Nicholas, Kemp Paul R, Moxham John, Polkey Michael I, Hopkinson Nicholas S
Dept of Palliative Care, Policy and Rehabilitation, King's College London, London, UK Dept of Asthma, Allergy and Lung Biology, King's College London, London, UK Both authors contributed equally.
National Heart and Lung Institute, NIHR Respiratory Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London, UK Both authors contributed equally.
Eur Respir J. 2014 Nov;44(5):1188-98. doi: 10.1183/09031936.00066414. Epub 2014 Jul 3.
Quadriceps muscle phenotype varies widely between patients with chronic obstructive pulmonary disease (COPD) and cannot be determined without muscle biopsy. We hypothesised that measures of skeletal muscle adiposity could provide noninvasive biomarkers of muscle quality in this population. In 101 patients and 10 age-matched healthy controls, mid-thigh cross-sectional area, percentage intramuscular fat and skeletal muscle attenuation were calculated using computed tomography images and standard tissue attenuation ranges: fat -190- -30 HU; skeletal muscle -29-150 HU. Mean±sd percentage intramuscular fat was higher in the patient group (6.7±3.5% versus 4.3±1.2%, p = 0.03). Both percentage intramuscular fat and skeletal muscle attenuation were associated with physical activity level, exercise capacity and type I fibre proportion, independent of age, mid-thigh cross-sectional area and quadriceps strength. Combined with transfer factor of the lung for carbon monoxide, these variables could identify >80% of patients with fibre type shift with >65% specificity (area under the curve 0.83, 95% CI 0.72-0.95). Skeletal muscle adiposity assessed by computed tomography reflects multiple aspects of COPD related muscle dysfunction and may help to identify patients for trials of interventions targeted at specific muscle phenotypes.
慢性阻塞性肺疾病（COPD）患者的股四头肌表型差异很大，不经肌肉活检无法确定。我们假设骨骼肌脂肪含量的测量可以为该人群提供肌肉质量的非侵入性生物标志物。在101例患者和10名年龄匹配的健康对照中，使用计算机断层扫描图像和标准组织衰减范围计算大腿中部横截面积、肌内脂肪百分比和骨骼肌衰减：脂肪-190至-30 HU；骨骼肌-29至150 HU。患者组的平均±标准差肌内脂肪百分比更高（6.7±3.5%对4.3±1.2%，p = 0.03）。肌内脂肪百分比和骨骼肌衰减均与身体活动水平、运动能力和I型纤维比例相关，独立于年龄、大腿中部横截面积和股四头肌力量。结合肺一氧化碳转移因子，这些变量可以识别>80%的纤维类型转变患者，特异性>65%（曲线下面积0.83，95%CI 0.72-0.95）。通过计算机断层扫描评估的骨骼肌脂肪含量反映了COPD相关肌肉功能障碍的多个方面，可能有助于识别适合针对特定肌肉表型进行干预试验的患者。
