OBJECTIVE: To probe into the clinical significance of expression of serum procalcitonin（PCT） and D-dimer（D-D） levels in elderly patients with acute exacerbation of chronic obstructive pulmonary disease（AECOPD） and the effect of aerosol treatment with acetylcysteine on prognosis. METHODS: Totally 100 elderly patients with AECOPD admitted into this hospital from Feb. 2018 to Feb. 2020 were selected as study subjects

the baseline data were recorded when admission

the serum parameters（PCT

D-D） were also measured and recorded

and patients were treated with acetylcysteine nebulizer for 2 courses（5 days as a course of treatment）. All patients were followed up for 1 year after discharge

and were divided into poor prognosis group[frequent acute exacerbations（the frequency of acute exacerbations ≥twice a year）] and favourable prognosis group（no frequent acute exacerbations） based on the results of follow-up visit

the baseline data and serum indicators of the two groups were compared to emphatically analyze the effects of serum PCT and D-D levels on the prognosis in elderly patients with AECOPD before treatment. RESULTS: At one-year follow-up after treatment

47 of 100 elderly patients with AECOPD had frequent acute exacerbations

with the incidence of poor prognosis was 47.00%. Patients in the poor prognosis group had higher lung function Gold grade

lower forced expiratory volume in 1 s and arterial partial pressure of oxygen

higher pulmonary artery systolic pressure

arterial partial pressure of carbon dioxide

PCT and D-D levels than those of the favourable prognosis group

with statistically significant differences（P<0.05）. Results of logistic regression analysis indicated that PCT and D-D were associated with poor prognosis of acetylcysteine nebulizer therapy in elderly patients with AECOPD（P<0.05）

elevated PCT and D-D were the influence factors of poor prognosis of acetylcysteine nebulizer therapy in elderly patients with AECOPD（OR>1

P<0.05）; plotting ROC curves showed that the AUC for serum PCT and D-D alone and combined prediction on poor prognosis in elderly patients with AECOPD treated with acetylcysteine nebulizer at admission were respectively 0.711

0.708 and 0.754 to predict

all of which had certain predictive value. CONCLUSIONS: The expression of serum PCT and D-D levels in elderly patients with AECOPD can predict poor prognosis of acetylcysteine nebulizer therapy

the elevation of PCT and D-D levels has increased the risk of poor prognosis of acetylcysteine nebulizer therapy in elderly patients with AECOPD.