Abstract:Objective To investigate the relationship between the level of plasma D-dimer(D-D) and the prognosis of patients with chronic obstructive pulmonary disease(COPD) and low-risk pulmonary embolism(PE). Methods A total of 117 COPD patients from January 2016 to September 2018 were selected and divided into COPD group (n=55) and COPD with PE group (n=62) according to whether the patients had low-risk PE or not.In the same period,52 healthy outpatients were served as control group.The levels of plasma D-D,PT,APTT,FIB,CRP,WBC,forced expiratory volume in 1s as a percentage of predicted value(FEV₁% pred),forced expiratory volume in 1s as a percentage of forced vital capacity(FEV₁/FVC) and diffusing capacity of the lung for carbon monoxide(DL_CO) were measured among three groups.Multivariate Logistic stepwise regression was used to investigate the risk factors of death in COPD patients with low-risk PE. Results PT,APTT,FEV₁%,FEV₁/FVC and DL_CO decreased in the order of control group,COPD group and COPD with PE group(all P<0.01),and FIB,CRP,WBC and D-D increased statistically in the order of control group,COPD group and COPD with PE group(all P<0.01).D-D level statistically increased with the increase of hypoxemia severity(P<0.05).D-D was negatively correlated with FEV₁%,FEV₁/FVC,DL_CO,PT,APTT,and was positively correlated with CRP,WBC and FIB(P<0.05,P<0.01).High level of D-D and low levels of FEV₁/FVC and APTT were the risk factors for death in COPD patients with low-risk PE(all P<0.01).The areas under ROC curves (AUC) of FEV₁/FVC and APTT were similar,but less than D-D.In the diagnosis of COPD patients with low-risk PE,the sensitivity and specificity of FEV₁/FVC and APTT were similar (all P>0.05),and both were less than those of D-D (all P<0.05). Conclusion The plasma D-D plays an important role in the diagnosis and prognosis of COPD patients with low-risk PE.