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. Aims 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 (m MRC ) 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 m MRC 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 m MRC 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 m MRC and PS at the 3‐month and 1‐year follow ups, after adjustment for other prognostic predictors. Conclusion Obvious emphysematous changes on CT ( LAA % > 7.5%) during an AECOPD predicts a poor prognosis independent of other known indicators.