Serum Creatinine to Cystatin C Ratio is an Effective Indicator for Muscle Strength Decline in Men with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Dan Huang,* Canhui Xie,* Chaoqun Sun,* Min Chen, Lian Li, Huajuan Yi, Jinyu Liao, Xuanna Zhao, Xiaoping Shen, Donglan He, Dongming Li, Dong Wu Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People’s Republic of China*These authors contributed equally to this workCorrespondence: Dong Wu; Dongming Li, Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Guangdong Medical University, 57th South Renmin Road, Zhanjiang, 524001, Guangdong, People’s Republic of China, Tel/Fax +867592387413, Email wudong98@126.com; 1335887835@qq.comPurpose: This study explored the value of the serum creatinine/cystatin C (Cr/CysC) ratio in diagnosing the reduction of muscle strength in men with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).Patients and Methods: In this study, we enrolled 72 male patients with AECOPD and 32 male patients with stable chronic obstructive pulmonary disease (COPD). We compared clinical characteristics between the AECOPD and stable COPD groups. Then, we subdivided AECOPD patients into normal muscle strength and low muscle strength groups; we compared the clinical characteristics between these two groups. We analyzed the relationships of serum creatinine (Cr), cystatin C (CysC), and Cr/CysC ratio with clinical characteristics in male AECOPD patients. We also investigated whether the Cr/CysC ratio could aid in the diagnosis of muscle strength decline via receiver operating characteristic curve and binary logistic regression analysis.Results: We found that handgrip strength, Cr/CysC ratio, serum Cr, FEV1, FVC, and FEV1%pred were lower in AECOPD patients than in stable COPD patients. Among AECOPD patients, BMI, weight, FEV1, FVC, FEV1%pred, and Cr/CysC ratio were lower in the low muscle strength group than in the normal muscle strength group; there were more patients with ≥ 2 acute exacerbations within the past ye