Current situation of asthma-COPD overlap in Chinese patients older than 40 years with airflow limitation: a multicenter, cross-sectional, non-interventional study

Frailty in asthma-COPD overlap: a cross-sectional study of association and risk factors in the NHANES database

BACKGROUND

Asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) is a condition characterised by the simultaneous presence of features of both asthma and COPD. The study aims to investigate the association between ACO and frailty among middle-aged and elderly populations, and identify the risk factors for frailty in individuals with ACO.

METHODS

We conducted a cross-sectional study with 34 403 eligible participants (aged ≥40 years) from the National Health and Nutrition Examination Survey 1999-2018 cycles. Participants were stratified into four groups: ACO, asthma, COPD and non-asthma/COPD. Frailty assessment was based on frailty index, generating frail and non-frail group. Univariate and multivariate survey-weighted logistic regression analysis were used to determine the association between ACO and frailty, and to identify the risk factors for frailty in ACO.

RESULTS

The frailty prevalence in participants with ACO was 60.2%, significantly higher than that in those with asthma (32.3%) and COPD (40.6%). In the unadjusted model, participants with ACO exhibited six-fold higher odds of frailty (OR 6.30, 95% CI 5.29 to 7.49), which was significantly greater than those with COPD (OR 2.84, 95% CI 2.46 to 3.28) and asthma (OR 1.99, 95% CI 1.80 to 2.18), using the non-asthma/COPD group as a reference. After adjusting for all confounders, participants with ACO had over four times higher odds of frailty (OR 4.48, 95% CI 3.53 to 5.71), still higher than those with asthma and COPD. The findings remained robust in sensitivity and subgroup analyses. Furthermore, hypertension, cancer, cardiovascular disease, chronic kidney disease and cognitive disorders were identified as risk factors for frailty among ACO participants, while higher income and education levels were protective factors.

CONCLUSION

Patients (aged ≥40 years) with ACO were at a higher risk of frailty, regardless of age or sex, compared with those with asthma or COPD alone. Greater attention should be paid to patients with ACO, regardless of their age.

COPD Patients with Asthma Features in Vietnam: Prevalence and Suitability for Personalized Medicine

COPD patients with asthma features usually benefit from inhaled corticosteroids (ICS)-containing regimens, but their burden and diagnostic criteria remain to be established. The aims of this study were to estimate the proportion of patients with asthma features among patients with physician-diagnosed COPD and to investigate differences in clinical characteristics and current medications between COPD patients with asthma features and patients with COPD alone. A cross-sectional study was conducted at two respiratory out-patient clinics at the University Medical Center in Ho Chi Minh City and Bach Mai Hospital in Ha Noi, Vietnam. COPD patients with asthma features were identified by attending physicians following the approach recommended by the GINA/GOLD joint committee. Of the 332 patients screened, 300 were enrolled in the study. The proportion of COPD patients with asthma features was 27.3% (95% confidence interval (95% CI) 22.6-32.6%). COPD patients with asthma features were younger, with higher FEV₁ values, a greater proportion of positive bronchodilator reversibility tests, higher blood eosinophil count, and were more often treated with ICS/LABA (ICS/long-acting bronchodilator beta-2 agonist) than patients with COPD alone. The prevalence of COPD patients with asthma features is particularly high in Vietnam thus requiring appropriate action plans in clinical practice.

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

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 (FEV₁)% 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 FEV₁% 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 FEV₁% 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.