Asthma-COPD overlap syndrome showed more exacerbations however lower mortality than COPD

Abstract

Background: Asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) is a new determinate syndrome whose exact characteristics remain unclear.

Aim: The objective of this study is to find more difference between ACOS and COPD.

Design: A retrospective study of ACOS and COPD in Chinese.

Methods: Data from 65 patients with ACOS and 65 patients with COPD were retrospectively collected and analyzed. The basis of this study was to compare the two groups while ruling out differences in age, sex and smoking history.

Results: Patients with ACOS tended to have earlier ages of onset, longer durations of symptoms, better nutritional status, higher single-breath diffusing capacity of carbon monoxide (DLCO) %predicted and airway resistance %predicted, more exacerbations in the preceding 12 months and shorter lengths of hospitalization. DLCO %predicted, airway resistance %predicted, and length of hospitalization were the variables most significantly associated with the presence of ACOS in patients with COPD. ROC correlating airway resistance %predicted value and current ACOS showed an optimal cutoff of airway resistance %predicted of over 296.6. During follow-up (median: 45 months; interquartile range: 6-82 months), 16 patient deaths were recorded (3 patients with ACOS). The risk remained significantly higher in patients with COPD alone than in patients with ACOS (HR 3.932; 95% CI 1.083-19.755; P = 0.046).

Conclusion: Patients with ACOS were more likely to have better prognoses and lower mortality than those with COPD alone, though with greater exacerbation frequency.