ObjectiveTo observe the dynamic changes of plasma Clara cell secretory protein (CC16) in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD), and to explore its role in the occurrence and development of the disease and clinical significance.MethodsA total of 71 AECOPD patients were included in this study as observation group. All subjects completed the CAT questionnaire and were sampled 2 ml of venous blood on day 1 and day 7 after their admission. And the percentage of forced expiratory volume in the first second (FEV1%pred), percentage of forced vital capacity in the estimated value (FVC%pred), FEV1/FVC ratio, arterial partial pressure of carbon dioxide (PaCO2), white blood cell count (WBC), the proportion of neutrophils (NEUT%), C-reactive protein (CRP), procalcitonin (PCT) and the length of stay of subjects were recorded. Another 20 healthy adults were enrolled as the control group. Each subject of the control group was sampled 2 ml of venous blood. The plasma CC16 levels of the two groups were tested and compared, and analyzed its correlation with CAT score and length of stay.ResultsThe plasma CC16 level of AECOPD patients was significantly lower than that of the control group, lung function was significantly lower than that of the healthy control group, WBC and NEUT% were significantly higher than that of the healthy control group, and the difference was statistically significant (P<0.05). Compared with day 1 after admission, the plasma CC16 level, CAT score, PaCO2, WBC, NEUT%, CRP, PCT of AECOPD patients on day 7 were significantly decreased, with statistically significant differences (P<0.05). The plasma CC16 level of AECOPD patients was negatively correlated with their CAT score (r=–0.704, P<0.001), and also was negatively correlated with the length of stay (r=–0.351, P=0.003).ConclusionsCC16 is involved in the development and progression of AECOPD and closely related to the severity and prognosis of the disease. Its dynamic changes can predict the condition changes and evaluate the clinical treatment effect of patients with AECOPD. Combined with common clinical indicators, CC16 can shorten the length of stay of patients.