title: Obvious emphysema on computed tomography during an acute exacerbation of chronic obstructive pulmonary disease predicts a poor prognosis.
abstract: BACKGROUND
  Emphysematous change on computed tomography (CT) during the stable phase of chronic obstructive pulmonary disease (COPD) is reported to correlate with COPD prognosis. Acute exacerbation of COPD (AECOPD) is associated with a high risk of mortality and a poor prognosis.
  
  
  OBJECTIVE
  This study aims to study the relationship between prognosis and emphysematous changes on CT during an AECOPD.
  
  
  METHODS
  Histories were recorded, and CT acquired for 106 patients who visited the emergency department for an AECOPD. Emphysematous change was quantified by measuring the percentage of low-attenuation areas (LAA%) in the entire lung on CT images with a threshold of -950 Hounsfield units. Other factors that could influence AECOPD prognosis were also recorded on admission and analysed. At follow ups conducted in 1 year, patient survival, the modified Medical Research Council (mMRC) Dyspnoea Scale, and performance status (PS) were evaluated, and a COPD Assessment Test (CAT) was completed.
  
  
  RESULTS
  The 1-year follow up was completed by 103 of 106 patients. The median LAA% was significantly higher in non-survivors (11%, n = 16) than in survivors (5.69%, n = 87) (P = 0.006) at the 1-year follow up. LAA% was significantly correlated with mMRC grade (r = 0.285, P = 0.008), PS (r = 0.397, P < 0.001) and CAT score (r = 0.27, P = 0.017) at the 3-month follow up, and with mMRC grade (r = 0.405, P < 0.001) and PS (r = 0.377, P < 0.001) at the 1-year follow up. LAA% > 7.5% was a significant predictor of 1-year mortality, higher mMRC and PS at the 3-month and 1-year follow ups, after adjustment for other prognostic predictors.
  
  
  CONCLUSIONS
  Obvious emphysematous changes on CT (LAA% > 7.5%) during an AECOPD predicts a poor prognosis independent of other known indicators.
authors: Department of Respiratory Medicine, Ruijin Hospital, North, China.
authors: T
authors: T
authors: Cheng
authors: Department of Respiratory Medicine, Ruijin Hospital, North, China.
authors: H Y
authors: HY
authors: Wan
authors: Department of Respiratory Medicine, Ruijin Hospital, North, China.
authors: Q J
authors: QJ
authors: Cheng
authors: Department of Respiratory Medicine, Ruijin Hospital, Shanghai, China.
authors: Y
authors: Y
authors: Guo
authors: Department of Respiratory Medicine, Ruijin Hospital, Shanghai, China.
authors: Y R
authors: YR
authors: Qian
authors: Department of Respiratory Medicine, Ruijin Hospital, Shanghai, China.
authors: L
authors: L
authors: Fan
authors: Department of Respiratory Medicine, Ruijin Hospital, Shanghai, China.
authors: Y
authors: Y
authors: Feng
authors: Department of Biostatistics, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors: Y Y
authors: YY
authors: Song
authors: Department of Respiratory Medicine, Ruijin Hospital, Shanghai, China.
authors: M
authors: M
authors: Zhou
authors: Department of Respiratory Medicine, Ruijin Hospital, Shanghai, China.
authors: Q Y
authors: QY
authors: Li
authors: Department of Respiratory Medicine, Ruijin Hospital, Shanghai, China.
authors: G C
authors: GC
authors: Shi
authors: Department of Respiratory Medicine, Ruijin Hospital, Shanghai, China.
authors: S G
authors: SG
authors: Huang
mesh_terms: D000208:Acute Disease; D000368:Aged; D002681:China / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000000981:diagnostic imaging / Q000401:mortality; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging / Q000209:etiology* / Q000401:mortality; D015996:Survival Rate; D014057:Tomography, X-Ray Computed
keywords: X-ray computed; acute exacerbation of chronic obstructive pulmonary disease (AECOPD); chronic obstructive; emphysema; prognosis; pulmonary disease; tomography