Department of Pulmonology, Hospital Universitario Marqués de Valdecilla, Santander, Spain,
Department of Clinical Biochemistry, Hospital Universitario Marqués de Valdecilla, Santander, Spain.
Respiration. 2019;97(4):302-309. doi: 10.1159/000494296. Epub 2018 Nov 27.
In chronic obstructive pulmonary disease (COPD), low muscle mass has been associated with several clinical outcomes such as low exercise capacity, hospital admission, and mortality. The Sarcopenia Index (SI) is a novel way to estimate muscle mass based on the ratio of serum creatinine (produced exclusively by muscle)/cystatin C (produced by all nucleated body cells).
This study aims to assess the SI in stable COPD outpatients, as compared with a healthy control group, to quantify its relationship with several important clinical features in COPD, and to study its potential usefulness to predict COPD exacerbations and hospital admissions.
The SI was calculated in 18 healthy control subjects and 65 stable COPD outpatients were included in the study. Patients were prospectively followed for 1 year after being enrolled in the study.
COPD patients had a lower SI than controls, that is lower muscle mass. Furthermore, patients with a modified Medical Research Council dyspnea score ≥2, patients with a COPD Assessment Test score ≥10, and patients with a high risk of exacerbation had lower levels of SI compared with patients without these characteristics. SI correlated with FEV1 (r = 0.491, p < 0.001), the 6-min walking test (r = 0.560, p = 0.001), and the Fat-Free Mass Index (r = 0.431, p = 0.017). Univariate and multivariate Cox proportional risk analysis showed that a low SI is an independent predictor of hospital admission in COPD outpatients followed for 1 year (HR 5.16, p = 0.025).
The ratio serum creatinine/serum cystatin C correlates with several COPD characteristics, and it can be used to predict COPD hospitalization.
在慢性阻塞性肺疾病（COPD）中，低肌肉量与多种临床结局相关，如运动能力降低、住院和死亡。肌少症指数（SI）是一种基于血清肌酐（肌肉产生）/胱抑素 C（所有有核细胞产生）比值来估计肌肉量的新方法。
本研究旨在评估稳定期 COPD 门诊患者的 SI，并与健康对照组进行比较，以量化其与 COPD 多个重要临床特征的关系，并研究其预测 COPD 加重和住院的潜在用途。
在 18 名健康对照组和 65 名稳定期 COPD 门诊患者中计算了 SI。患者在入组后进行了为期 1 年的前瞻性随访。
COPD 患者的 SI 低于对照组，即肌肉量较低。此外，改良的医学研究委员会呼吸困难评分≥2 分、COPD 评估测试评分≥10 分和高加重风险的患者的 SI 水平低于无这些特征的患者。SI 与 FEV1（r = 0.491，p < 0.001）、6 分钟步行试验（r = 0.560，p = 0.001）和无脂肪质量指数（r = 0.431，p = 0.017）相关。单变量和多变量 Cox 比例风险分析显示，低 SI 是 COPD 门诊患者随访 1 年时住院的独立预测因素（HR 5.16，p = 0.025）。
血清肌酐/血清胱抑素 C 比值与 COPD 的多个特征相关，可用于预测 COPD 住院。
