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Clinical indicators for asthma-COPD overlap: a systematic review and meta-analysis
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  • Junjie Peng,
  • Min Wang,
  • Yanqiu Wu,
  • Yongchun Shen,
  • Lei Chen
Junjie Peng
Sichuan University West China Hospital

Corresponding Author:[email protected]

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Min Wang
Yanqiu Wu
Yongchun Shen
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Lei Chen
Sichuan University West China Hospital
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Background: Some clinical indicators have been reported to be useful in differentiating asthma-COPD overlap (ACO) from pure COPD/asthma, but the results were inconsistent. This study aims to evaluate the diagnostic value of these indicators for ACO. Methods: Databases of PubMed, EMBASE, Ovid and Web of Science were retrieved. Pooled standardized mean difference (SMD) with 95%CI was calculated in random effects model. Heterogeneity was explored through I-squared statistic. Publication bias was assessed via funnel-plot with begg’s and egger’s tests. Results: 46 eligible studies were included. The pooled results indicated, compared with pure COPD, ACO patients had higher FEV 1% (SMD=0.16, 95%CI 0.05 to 0.27), DLCO% (SMD=0.38, 95%CI 0.16 to 0.6), FeNO (SMD=0.58, 95%CI 0.38 to 0.78), serum total IgE (SMD=0.42, 95%CI 0.07 to 0.76), blood eosinophil (SMD=0.43, 95%CI 0.26 to 0.61), percentage of induced sputum eosinophil (SMD=0.62, 95%CI 0.42 to 0.83), and lower percentage of induced sputum neutrophil (SMD=-0.48, 95%CI -0.7 to -0.27), circulating YKL-40 (SMD=-1.09, 95%CI -1.92 to -0.26). However, compared with asthma alone, ACO patients had lower FEV 1% (SMD=-1.1, 95%CI -1.32 to -0.87), DLCO% (SMD=-0.83, 95%CI -1.24 to -0.42), FeNO (SMD=-0.25, 95%CI -0.38 to -0.11), and higher percentage of induced sputum neutrophil (SMD=0.51, 95%CI 0.21 to 0.81), circulating YKL-40 (SMD=0.96, 95%CI 0.27 to 1.64). Conclusions: Compared with pure COPD/asthma, ACO patients have different levels of FEV 1%, DLCO%, FeNO, serum total IgE, blood eosinophil, percentage of induced sputum eosinophil/neutrophil, and circulating YKL-40, which could be helpful to establish a clinical diagnosis of ACO. More studies are warranted to validate these findings.