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      Clinical characteristics of chronic bronchitic, emphysematous and ACOS phenotypes in COPD patients with frequent exacerbations

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          Chronic bronchitis (CB), emphysematous (EM) and asthma–chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) phenotypes in COPD are well recognized. This study aimed to investigate distinguishing characteristics of these phenotypes in COPD patients with frequent exacerbations (FE).

          Patients and methods

          A retrospective study was carried out. COPD patients with acute exacerbations were consecutively reviewed from November 2015 to October 2016. Patients were divided into FE and infrequent exacerbations (iFE) subgroups.


          A total of 142 eligible COPD subjects were reviewed. In the CB phenotype subgroup, age, body mass index, forced expiratory volume in 1 second (FEV 1) % predicted, COPD assessment test (CAT), modified Medical Research Council breathlessness measurement (mMRC) dyspnea scale, emphysema scores and arterial carbon dioxide pressure (PaCO 2) were significantly different in subjects with FE when compared to those in subjects with iFE of CB. In the EM phenotype subgroup, age, CAT, mMRC scores and history of COPD were different in subjects with FE when compared to those in CB subjects with iFE. Multivariate analysis indicated that FEV 1% predicted (odds ratio [OR] =0.90, P=0.04) and PaCO 2 (OR =1.22, P=0.02) were independent risk factors for FE in COPD with CB phenotype, and CAT (OR =2.601, P=0.001) was the independent risk factor for FE in COPD with EM phenotype. No significant differences in characteristics were observed in ACOS phenotype subgroups with FE or iFE.


          In CB or EM phenotypes, COPD patients with FE present several differential clinical characteristics compared to patients with iFE, while the characteristics of ACOS phenotype in patients with FE need more investigation.

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          Most cited references 30

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          Chronic obstructive pulmonary disease exacerbations in the COPDGene study: associated radiologic phenotypes.

          To test the hypothesis-given the increasing emphasis on quantitative computed tomographic (CT) phenotypes of chronic obstructive pulmonary disease (COPD)-that a relationship exists between COPD exacerbation frequency and quantitative CT measures of emphysema and airway disease. This research protocol was approved by the institutional review board of each participating institution, and all participants provided written informed consent. One thousand two subjects who were enrolled in the COPDGene Study and met the GOLD (Global Initiative for Chronic Obstructive Lung Disease) criteria for COPD with quantitative CT analysis were included. Total lung emphysema percentage was measured by using the attenuation mask technique with a -950-HU threshold. An automated program measured the mean wall thickness and mean wall area percentage in six segmental bronchi. The frequency of COPD exacerbation in the prior year was determined by using a questionnaire. Statistical analysis was performed to examine the relationship of exacerbation frequency with lung function and quantitative CT measurements. In a multivariate analysis adjusted for lung function, bronchial wall thickness and total lung emphysema percentage were associated with COPD exacerbation frequency. Each 1-mm increase in bronchial wall thickness was associated with a 1.84-fold increase in annual exacerbation rate (P = .004). For patients with 35% or greater total emphysema, each 5% increase in emphysema was associated with a 1.18-fold increase in this rate (P = .047). Greater lung emphysema and airway wall thickness were associated with COPD exacerbations, independent of the severity of airflow obstruction. Quantitative CT can help identify subgroups of patients with COPD who experience exacerbations for targeted research and therapy development for individual phenotypes. © RSNA, 2011.
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            Consensus document on the overlap phenotype COPD-asthma in COPD.

            Although asthma and COPD are different pathologies, many patients share characteristics from both entities. These cases can have different evolutions and responses to treatment. Nevertheless, the evidence available is limited, and it is necessary to evaluate whether they represent a differential phenotype and provide recommendations about diagnosis and treatment, in addition to identifying possible gaps in our understanding of asthma and COPD. A nation-wide consensus of experts in COPD in two stages: 1) during an initial meeting, the topics to be dealt with were established and a first draft of statements was elaborated with a structured "brainstorming" method; 2) consensus was reached with two rounds of e-mails, using a Likert-type scale. Consensus was reached about the existence of a differential clinical phenotype known as"Overlap Phenotype COPD-Asthma", whose diagnosis is made when 2 major criteria and 2 minor criteria are met. The major criteria include very positive bronchodilator test (increase in FEV(1) ≥ 15% and ≥ 400ml), eosinophilia in sputum and personal history of asthma. Minor criteria include high total IgE, personal history of atopy and positive bronchodilator test (increase in FEV(1) ≥ 12% and ≥ 200ml) on two or more occasions. The early use of individually-adjusted inhaled corticosteroids is recommended, and caution must be taken with their abrupt withdrawal. Meanwhile, in severe cases the use of triple therapy should be evaluated. Finally, there is an obvious lack of specific studies about the natural history and the treatment of these patients. It is necessary to expand our knowledge about this phenotype in order to establish adequate guidelines and recommendations for its diagnosis and treatment. Copyright © 2011 SEPAR. Published by Elsevier Espana. All rights reserved.
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              Clinical phenotypes of COPD: identification, definition and implications for guidelines.

              The term phenotype in the field of COPD is defined as "a single or combination of disease attributes that describe differences between individuals with COPD as they relate to clinically meaningful outcomes". Among all phenotypes described, there are three that are associated with prognosis and especially are associated with a different response to currently available therapies. There phenotypes are: the exacerbator, the overlap COPD-asthma and the emphysema-hyperinflation. The exacerbator is characterised by the presence of, at least, two exacerbations the previous year, and on top of long-acting bronchodilators, may require the use of antiinflammatory drugs. The overlap phenotype presents symptoms of increased variability of airflow and incompletely reversible airflow obstruction. Due to the underlying inflammatory profile, it uses to have a good therapeutic response to inhaled corticosteroids in addition to bronchodilators. Lastly, the emphysema phenotype presents a poor therapeutic response to the existing antiinflammatory drugs and long-acting bronchodilators together with rehabilitation are the treatments of choice. Identifying the peculiarities of the different phenotypes of COPD will allow us to implement a more personalised treatment, in which the characteristics of the patients, together with their severity will be key to choose the best treatment option. Copyright © 2011 SEPAR. Published by Elsevier Espana. All rights reserved.

                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
                18 July 2017
                : 12
                : 2069-2074
                Department of Respiratory Medicine, Yijishan Hospital of Wannan Medical College, Wuhu, People’s Republic of China
                Author notes
                Correspondence: Xingwu Chen, Department of Respiratory Medicine, Yijishan Hospital of Wannan Medical College, 2 Zeshan West Road, Jinghu, Wuhu, Anhui, 241001, People’s Republic of China, Tel +86 553 573 9229, Email yjscxw2006@

                These authors contributed equally to this work

                © 2017 Cheng 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

                frequent exacerbations, chronic bronchitis, copd, acos, emphysema


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