In the univariate cox regression analysis, FVC/DLCO was an independent predictor of 5-year all-cause mortality in COPD patients (HR = 3.33, 95%CI 2.16–5.13, P < 0.001), along with age, BMI, FEV1%, FVC%, VA%, DLCO%, the comorbidity (hypertension, coronary heart disease or PH), pH, PaO2, PaCO2, neutrophil count, albumin and cystatin C. And the inhalation therapy had no significant effect on the 5-year all-cause mortality of COPD patients. This evidence concerns the gene CST3 and chronic obstructive pulmonary disease.