Clinical Indicators for Asthma-COPD Overlap: A Systematic Review and Meta-Analysis

Abstract

Background Some clinical indicators have been reported to be useful in differentiating asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) from pure asthma/COPD, 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 differences (SMDs) with 95% confidence intervals (CIs) were calculated in random-effects models. Results 48 eligible studies were included. The pooled results indicated, compared with pure asthma, ACO patients had lower levels of forced expiratory volume in the first second (FEV 1 )% predicted (pred) (SMD=−1.09, 95% CI −1.3 to −0.87), diffusion lung capacity for carbon monoxide (DLCO)% pred (SMD=−0.83, 95% CI −1.24 to −0.42), fractional exhaled nitric oxide (FeNO) (SMD=−0.23, 95% CI −0.36 to −0.11), and higher levels 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). However, relative to COPD alone, ACO patients had higher levels of FEV 1 % pred (SMD = 0.15, 95% CI 0.05 to 0.26), DLCO% pred (SMD = 0.38, 95% CI 0.16 to 0.6), FeNO (SMD = 0.59, 95% CI 0.40 to 0.78), serum total immunoglobulin (Ig)E (SMD = 0.42, 95% CI 0.1 to 0.75), blood eosinophil (SMD = 0.44, 95% CI 0.29 to 0.59), induced sputum eosinophil (SMD = 0.62, 95% CI 0.42 to 0.83), and lower levels 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). Conclusion Compared with pure asthma/COPD, ACO patients have different levels of FEV 1 % pred, DLCO% pred, FeNO, serum total IgE, blood eosinophil, induced sputum eosinophil/neutrophil, and circulating YKL-40, which could be helpful to establish a clinical diagnosis of ACO.

The value of bronchodilator response in FEV1 and FeNO for differentiating between chronic respiratory diseases: an observational study

“…We thought the reason for this phenomenon was that the positive BDT result and exposure to tobacco smoke reduced the difference in BECs between ACO and COPD or asthma [ 34 – 36 ]. Peng reported that patients with ACO had higher BECs than those with COPD [ 37 ]. However, there was no difference in BECs among the asthma, COPD, and ACO groups in the real-world study cohort, NOVELTY [ 6 ].…”

Using inflammatory index to distinguish asthma, asthma-COPD overlap and COPD: A retrospective observational study

“…Although our research shows that inflammatory biomarkers can distinguish CRD, the clinical application value is still in the exploration stage. We mainly differentiate CRD according to diagnostic criteria and some clinical indicators that can reflect the characteristics of the disease (e.g., fractional exhaled nitric oxide, total immunoglobulin E, allergy tests, et al) (48)(49)(50). Inflammatory biomarkers are just another auxiliary means for the hard-to-distinguish CRD.…”

Serum YKL-40 Levels in Patients with Asthma or COPD: A Pilot Study

“…This exploratory pilot study used a retrospective cross-sectional design to evaluate the practical relevance of YKL-40 (and other blood parameters) to delineate between BA subjects and COPD subjects. To the best of our knowledge, such basic information is lacking in Europe and is scarce around the world [ 18 , 19 , 20 ]. Hence, a group of age- and sex- matched patients was selected in order to obtain evidence-based information about the clinical applicability of these biomarkers.…”