title: Should the cut-off value of D-dimer be elevated to exclude pulmonary embolism in acute exacerbation of COPD?
abstract: OBJECTIVE
  The aim of this study was to evaluate the D-dimer levels in patients with chronic obstructive pulmonary disease (COPD) exacerbation with and without pulmonary embolism (PE) and to attempt to define a new cut-off value for D-dimer to exclude the diagnosis of PE in patients with COPD exacerbation.
  
  
  METHODS
  This cross-sectional study was performed between the June 2012 and January 2013. The COPD patients who were admitted to the emergency department with acute exacerbation were consecutively included. D-dimer levels were measured upon admission. All patients underwent computed tomography angiography (CTA) and Doppler ultrasonography (US) of the lower extremities.
  
  
  RESULTS
  A total of 148 patients were enrolled. Fifty-three patients (36%) who did not have PE had higher than normal (>0.5 pg/mL) D-dimer levels. The D-dimer levels of the COPD patients with PE were significantly higher than those of the patients without PE (2.38±2.80 vs. 1.06±1.51 pg/mL) (P<0.001). The cut-off value for D-dimer in diagnosing PE in the COPD patients was 0.95 pg/mL. The area under the receiver operating characteristic (ROC) curve was 0.752±0.040 (95% CI: 0.672-0.831) (P<0.001).
  
  
  CONCLUSIONS
  This study showed that the D-dimer concentrations of COPD patients who are in the exacerbation period may be higher than normal, even without PE. The cut-off level for D-dimer was 0.95 pg/mL (sensitivity 70%, spesificity 71%) for the exclusion of PE in the patients with COPD exacerbation. The D-dimer cut-off value that is used to exclude PE in patients with acute exacerbation of COPD should be reevaluated to prevent the excessive use of further diagnostic procedures.
authors.affiliation: Ufuk University Faculty of Medicine, Department of Chest Diseases, Ankara, Turkey;
authors.forename: Evrim Eylem
authors.initials: EE
authors.lastname: Akpinar
authors.forename: Derya
authors.initials: D
authors.lastname: Hoşgün
authors.forename: Beyza
authors.initials: B
authors.lastname: Doğanay
authors.forename: Gökçe Kaan
authors.initials: GK
authors.lastname: Ataç
authors.forename: Meral
authors.initials: M
authors.lastname: Gülhan
keywords: Chronic obstructive pulmonary disease (COPD); D-dimer; pulmonary embolism (PE)