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      Heterogeneity of asthma and COPD overlap

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          Asthma and COPD are heterogeneous diseases. Patients with both disease features (asthma–COPD overlap [ACO]) are common. However, clinical characteristics and socio-economic burden of ACO are still controversial. The aim of this study was to identify the heterogeneity of ACO and to find out the subtypes with clinical impact among ACO subtypes.


          In the Korean National Health and Nutrition Examination Survey (KNHANES) conducted between 2007 and 2012, subjects who were ≥40 years and had prebronchodilator FEV 1/FVC <0.7 and FEV 1 ≥50% predicted were included. The presence or absence of self-reported wheezing was indicated by W+ or W− and used as an index of airway hyper-responsiveness. S+/S− was defined as subjects who were smokers/never smokers. The subjects were divided into the following four groups: W−S−, W−S+, W+S−, and W+S+. W+S− and W+S+ were asthma-predominant ACO and COPD-predominant ACO, respectively. KNHANES and linked National Health Insurance data were analyzed.


          The asthma-predominant ACO group showed the lowest socioeconomic status, FEV 1, FVC% predicted, and quality of life (QoL) levels. The COPD-predominant ACO group showed the highest hospitalization rate, outpatient medical cost, and total and outpatient health care utilization. COPD-predominant ACO was associated with exacerbations compared to the W−S− group (adjusted odds ratio [aOR], 1.79; 95% confidence interval [CI], 1.12–2.85; P=0.015) and W−S+ group (OR 2.11; 95% CI 1.43–3.10; P<0.001). COPD-predominant ACO was associated with increased medical cost.


          Asthma-predominant ACO individuals displayed poorer socioeconomic status and QoL compared to the COPD-predominant ACO group. The COPD-predominant ACO group displayed more frequent exacerbations and greater medical costs. Considering the heterogeneity of ACO, it is desirable to identify subtypes of ACO patients and appropriately allocate limited medical resources.

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          The clinical features of the overlap between COPD and asthma

          Background The coexistence of COPD and asthma is widely recognized but has not been well described. This study characterizes clinical features, spirometry, and chest CT scans of smoking subjects with both COPD and asthma. Methods We performed a cross-sectional study comparing subjects with COPD and asthma to subjects with COPD alone in the COPDGene Study. Results 119 (13%) of 915 subjects with COPD reported a history of physician-diagnosed asthma. These subjects were younger (61.3 vs 64.7 years old, p = 0.0001) with lower lifetime smoking intensity (43.7 vs 55.1 pack years, p = 0.0001). More African-Americans reported a history of asthma (33.6% vs 15.6%, p < 0.0001). Subjects with COPD and asthma demonstrated worse disease-related quality of life, were more likely to have had a severe COPD exacerbation in the past year, and were more likely to experience frequent exacerbations (OR 3.55 [2.19, 5.75], p < 0.0001). Subjects with COPD and asthma demonstrated greater gas-trapping on chest CT. There were no differences in spirometry or CT measurements of emphysema or airway wall thickness. Conclusion Subjects with COPD and asthma represent a relevant clinical population, with worse health-related quality of life. They experience more frequent and severe respiratory exacerbations despite younger age and reduced lifetime smoking history. Trial registration NCT00608764
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            The Asthma-COPD Overlap Syndrome.

            Although in textbooks asthma and chronic obstructive pulmonary disease (COPD) are viewed as distinct disorders, there is increasing awareness that many patients have features of both. This article reviews the asthma-COPD overlap syndrome.
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              Increased risk of exacerbation and hospitalization in subjects with an overlap phenotype: COPD-asthma.

              Several COPD phenotypes have been described; the COPD-asthma overlap is one of the most recognized. The aim of this study was to evaluate the prevalence of three subgroups (asthma, COPD, and COPD-asthma overlap) in the Latin American Project for the Investigation of Obstructive Lung Disease (PLATINO) study population, to describe their main characteristics, and to determine the association of the COPD-asthma overlap group with exacerbations, hospitalizations, limitations due to physical health, and perception of general health status (GHS). The PLATINO study is a multicenter population-based survey carried out in five Latin American cities. Outcomes were self-reported exacerbations (defined by deterioration of breathing symptoms that affected usual daily activities or caused missed work), hospitalizations due to exacerbations, physical health limitations, and patients' perception of their GHS obtained by questionnaire. Subjects were classified in three specific groups: COPD--a postbronchodilator (post-BD) FEV₁/FVC ratio of < 0.70; asthma--presence of wheezing in the last year and a minimum post-BD increase in FEV₁ or FVC of 12% and 200 mL; and overlap COPD-asthma--the combination of the two. Out of 5,044 subjects, 767 were classified as having COPD (12%), asthma (1.7%), and COPD-asthma overlap (1.8%). Subjects with COPD-asthma overlap had more respiratory symptoms, had worse lung function, used more respiratory medication, had more hospitalization and exacerbations, and had worse GHS. After adjusting for confounders, the COPD-asthma overlap was associated with higher risks for exacerbations (prevalence ratio [PR], 2.11; 95% CI, 1.08-4.12), hospitalizations (PR, 4.11; 95% CI, 1.45-11.67), and worse GHS (PR, 1.47; 95% CI, 1.18-1.85) compared with those with COPD. The coexisting COPD-asthma phenotype is possibly associated with increased disease severity.

                Author and article information

                Int J Chron Obstruct Pulmon Dis
                Int J Chron Obstruct Pulmon Dis
                International Journal of COPD
                International Journal of Chronic Obstructive Pulmonary Disease
                Dove Medical Press
                17 April 2018
                : 13
                : 1251-1260
                [1 ]Department of Internal Medicine, College of Medicine, Ewha Womans University
                [2 ]Department of Internal Medicine, Seoul St Mary’s Hospital, The Catholic University of Korea, Seoul
                [3 ]Big Data Division, Health Insurance Review and Assessment Service, Wonju
                [4 ]Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Konkuk University Chungju Hospital, Chungju
                [5 ]Department of Pulmonary and Critical Care Medicine, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine
                [6 ]Department of Internal Medicine, Konkuk University College of Medicine, Seoul
                [7 ]Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Medical Center, Hallym University College of Medicine, Anyang, Republic of Korea
                Author notes
                Correspondence: Jin Hwa Lee, Department of Internal Medicine, College of Medicine, Ewha Womans University, 1071, Anyangcheon-ro, Yangcheon-gu, Seoul 07985, Republic of Korea, Tel +82 2 2650 6007, Fax +82 2 2650 2076, Email jinhwalee@
                © 2018 Kim et al. This work is published and licensed by Dove Medical Press Limited

                The full terms of this license are available at and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License ( By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed.

                Original Research

                Respiratory medicine

                asthma, copd, overlap, heterogeneity, health care utilization, exacerbation


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