Intensive care medicine

Asthma

Surgery

Pulmonary disease

Immunology

Airway

Chronic cough

Chronic disease

Internal medicine

Medicine

Respiratory disease

Bronchiectasis

Disease

Lung

Pathology

CHEST Journal

The excessive and persistent inflammatory response to external or endogenous noxae is likely the common pathogenic mechanism to most chronic airway diseases. Among these, the most frequent respiratory diseases are asthma, usually triggered by respiratory allergens, and COPD, caused by chronic exposure to tobacco smoking or other toxic gases, with prevalence rates of 10% to 12%1Adeloye D. Chua S. Lee C. et al.Global and regional estimates of COPD prevalence: systematic review and meta-analysis.J Glob Health. 2015; 5: 020415Crossref PubMed Scopus (703) Google Scholar and 5% to 8%,2McShane P.J. Naureckas E.T. Tino G. Strek M.E. Non-cystic fibrosis bronchiectasis.Am J Respir Crit Care Med. 2013; 188: 647-656Crossref PubMed Scopus (270) Google Scholar respectively. Moreover, the prevalence rate of COPD increases with age, achieving 20% in individuals > 65 years of age.1Adeloye D. Chua S. Lee C. et al.Global and regional estimates of COPD prevalence: systematic review and meta-analysis.J Glob Health. 2015; 5: 020415Crossref PubMed Scopus (703) Google Scholar Fortunately, the scientific literature on the management of both asthma and COPD is vast, and updates have been available to health-care professionals for many years. However, one risk of overgeneralizing such a well-developed body of evidence is that frequently some patients have been given a diagnosis of asthma or COPD without a complete and proper diagnostic investigation. Nonspecific symptoms, such as cough and dyspnea, can easily be applied in support of an incorrect or incomplete diagnosis and delay initiation of appropriate therapy. Bronchiectasis is usually defined as a chronic airway disease characterized by permanent bronchial dilatations and recurrent symptoms such as cough, expectoration, and recurrent respiratory infections.3Anandan C. Nurmatov U. van Schayck O.C. Sheikh A. Is the prevalence of asthma declining? Systematic review of epidemiological studies.Allergy. 2010; 65: 152-167Crossref PubMed Scopus (424) Google Scholar It frequently presents with chronic airflow obstruction, or sometimes with bronchial hyperresponsiveness.2McShane P.J. Naureckas E.T. Tino G. Strek M.E. Non-cystic fibrosis bronchiectasis.Am J Respir Crit Care Med. 2013; 188: 647-656Crossref PubMed Scopus (270) Google Scholar Similar to asthma and COPD, the pathogenesis of bronchiectasis is thought to be driven by an excessive and sustained inflammatory response to different stimuli (mostly bacterial and mycobacterial infection). Typically, the inflammatory pattern of the bronchiectatic airway is neutrophilic and similar to COPD.2McShane P.J. Naureckas E.T. Tino G. Strek M.E. Non-cystic fibrosis bronchiectasis.Am J Respir Crit Care Med. 2013; 188: 647-656Crossref PubMed Scopus (270) Google Scholar Therefore, parallels between and overlap of bronchiectasis, asthma, and COPD are not surprising and can easily contribute to frequent diagnostic mistakes or delay in correct diagnosis. Misdiagnoses are additionally facilitated by the common occurrence of airflow obstruction in patients with primary bronchiectasis, occurring in > 50% of US Bronchiectasis Registry patients even though 60% were never smokers and an additional 38% former smokers.4Aksamit T.R. ÓDonnell A.E. Barker A. et al.Adult patients with bronchiectasis: a first look at the US Bronchiectasis Research Registry.Chest. 2017; 151: 982-992Abstract Full Text Full Text PDF PubMed Scopus (209) Google Scholar Bronchiectasis has been considered in the past a neglected disease because of infrequent diagnosis, scarce therapeutic options, and a paucity of literature. However, in the last decade, the development of several national and international registries and a marked increase in the number of scientific publications, including randomized clinical trials and guidelines, have begun to address the gap in knowledge associated with bronchiectasis.4Aksamit T.R. ÓDonnell A.E. Barker A. et al.Adult patients with bronchiectasis: a first look at the US Bronchiectasis Research Registry.Chest. 2017; 151: 982-992Abstract Full Text Full Text PDF PubMed Scopus (209) Google Scholar, 5Polverino E. Goeminne P.C. McDonnell M.J. et al.European Respiratory Society guidelines for the management of adult bronchiectasis.Eur Respir J. 2017; 50: 1700629Crossref PubMed Scopus (580) Google Scholar, 6Pasteur M.C. Bilton D. Hill A.T. British Thoracic Society guideline for non-CF bronchiectasis.Thorax. 2010; 65: i1-i58Crossref PubMed Scopus (505) Google Scholar, 7Martínez-García M.Á. Máiz L. Olveira C. et al.Spanish guidelines on treatment of bronchiectasis in adults.Arch Bronconeumol. 2018; 54: 88-98Crossref PubMed Scopus (10) Google Scholar Although the overall epidemiology is not completely known, different investigators have reported increasing prevalence rates of bronchiectasis in the general population. This finding might reflect greater awareness of bronchiectasis and more realistic epidemiologic estimations. For instance, in China, bronchiectasis has been estimated to affect 1.5% of women and 1.1% of men in the general population.8Lin J.L. Xu J.F. Qu J.M. Bronchiectasis in China.Annals Am Thorac Soc. 2016; 13: 609-616Crossref PubMed Scopus (41) Google Scholar In Europe, a recent English study showed that bronchiectasis prevalence increased from 300 to 350 cases per 100,000 inhabitants in 2004 to 485 to 566 cases per 100,000 inhabitants in 2013, and that prevalence among individuals > 70 years of age can be > 1,100 to 1,300 cases per 100,000 inhabitants,9Quint J.K. Millett E.R. Joshi M. et al.Changes in the incidence, prevalence and mortality of bronchiectasis in the UK from 2004-2013: a population based cohort study.Eur Resp J. 2016; 47: 186-193Crossref PubMed Scopus (306) Google Scholar with similar numbers in Spain.10Monteagudo M. Rodriguez-Blanco T. Barrecheguren M. et al.Prevalence and incidence of bronchiectasis in Catalonia, Spain: a population-based study.Resp Med. 2016; 121: 26-31Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar Similarly, in the United States, a prevalence of 812 to 1,100 cases per 100,000 inhabitants > 65 years of age between 2000 and 2013 and an 8% annual growth11Weycker D. Edelsberg J. Oster G. Tino G. Prevalence and economic burden of bronchiectasis.Clin Pulm Med. 2005; 12: 205-209Crossref Scopus (240) Google Scholar, 12Seitz A.E. Olivier K.N. Adjemian J. et al.Trends in bronchiectasis among Medicare beneficiaries in the United States, 2000 to 2007.Chest. 2012; 142: 432-439Abstract Full Text Full Text PDF PubMed Scopus (227) Google Scholar have been reported. These epidemiologic data are quite different from those reported in the late 20th century (192 cases per 100,000 in people > 65 years of age).13Weycker D. Hansen G.L. Seifer F.D. Prevalence and incidence of noncystic fibrosis bronchiectasis among US adults in 2013.Chron Resp Dis. 2017; 14: 1-8Crossref Scopus (85) Google Scholar Hence, recent studies from various geographic areas share similar conclusions: the prevalence of bronchiectasis is higher in women, higher at advanced age, and in general higher than previously appreciated. Potential limitations for these estimations are likely. First, results of these epidemiologic studies were based on analyses of computerized databases of medical records using diagnostic codes for different variables of interest or health-care claim data, leading to the risk of considerable selection bias. Second, although up to 19% of individuals > 65 years of age can be reported to have asymptomatic cylindrical bronchiectasis involving the lower lobes of the lungs, these radiologic abnormalities may not represent clinically significant bronchiectasis in absence of clinical manifestations.14Tan W.C. Hague C.J. Leipsic J. et al.Findings on thoracic computed tomography scans and respiratory outcomes in persons with and without chronic obstructive pulmonary disease: a population-based cohort study.PLoS One. 2016; 11: e0166745Crossref PubMed Scopus (51) Google Scholar On the other hand, clinically relevant bronchiectasis is likely to be still underestimated because of a number of factors including variable access to health-care resources in different geographic areas, diagnostic errors including patients with bronchiectasis being classified as having asthma or COPD, or inadequate use of CT scan for diagnosis. In addition, it is important to consider the high prevalence of bronchiectasis associated with severe asthma (20%-30%)15Gupta S. Siddiqui S. Haldar P. et al.Quantitative analysis of high-resolution computed tomography scans in severe asthma subphenotypes.Thorax. 2010; 65: 775-781Crossref PubMed Scopus (91) Google Scholar and severe COPD (20%-50%).16Ni Y. Shi G. Yu Y. Hao J. Chen T. Song H. Clinical characteristics of patients with chronic obstructive pulmonary disease with comorbid bronchiectasis: a systemic review and meta-analysis.Int J Chron Obstruct Pulmon Dis. 2015; 10: 1465-1975Crossref PubMed Scopus (85) Google Scholar Therefore, even considering the uncertainties of the approximate prevalence rates, bronchiectasis may represent the third most common chronic airway disease after asthma and COPD, particularly at advanced age. Moreover, given the clinical overlap with these respiratory diagnoses, an accurate diagnosis and differentiation from asthma and COPD becomes imperative. In fact, misdiagnoses can have substantial therapeutic and prognostic implications. For instance, macrolides and inhaled antibiotics have consensus use agreement for an indication in the treatment of bronchiectasis,4Aksamit T.R. ÓDonnell A.E. Barker A. et al.Adult patients with bronchiectasis: a first look at the US Bronchiectasis Research Registry.Chest. 2017; 151: 982-992Abstract Full Text Full Text PDF PubMed Scopus (209) Google Scholar, 8Lin J.L. Xu J.F. Qu J.M. Bronchiectasis in China.Annals Am Thorac Soc. 2016; 13: 609-616Crossref PubMed Scopus (41) Google Scholar, 9Quint J.K. Millett E.R. Joshi M. et al.Changes in the incidence, prevalence and mortality of bronchiectasis in the UK from 2004-2013: a population based cohort study.Eur Resp J. 2016; 47: 186-193Crossref PubMed Scopus (306) Google Scholar whereas bronchodilators have largely demonstrated their efficacy only in asthma17Global Initiative for Asthma - GINA. www.ginasthma.org. Accessed January 11, 2018.Google Scholar and COPD,18Vogelmeier C.F. Criner G.J. Martinez F.J. et al.Global strategy for the diagnosis, management, and prevention of chronic obstructive lung disease 2017 report. GOLD Executive Summary.Am J Respir Crit Care Med. 2017; 195: 557-582Crossref PubMed Scopus (1929) Google Scholar and inhaled corticosteroids mostly in asthma,17Global Initiative for Asthma - GINA. www.ginasthma.org. Accessed January 11, 2018.Google Scholar and to lesser extent in select patients with COPD.18Vogelmeier C.F. Criner G.J. Martinez F.J. et al.Global strategy for the diagnosis, management, and prevention of chronic obstructive lung disease 2017 report. GOLD Executive Summary.Am J Respir Crit Care Med. 2017; 195: 557-582Crossref PubMed Scopus (1929) Google Scholar Fortunately, the diagnosis of bronchiectasis is more objective relative to establishing a diagnosis of asthma and COPD because it is based on CT scan and clinical history (compatible symptoms).2McShane P.J. Naureckas E.T. Tino G. Strek M.E. Non-cystic fibrosis bronchiectasis.Am J Respir Crit Care Med. 2013; 188: 647-656Crossref PubMed Scopus (270) Google Scholar A thorough clinical history (including characteristic symptoms, history of infections, smoking habits, specific respiratory pathogens such as Pseudomonas aeruginosa or nontuberculous mycobacteria, etc) should raise the suspicion of bronchiectasis in select patients and guide complementary diagnostic tests.2McShane P.J. Naureckas E.T. Tino G. Strek M.E. Non-cystic fibrosis bronchiectasis.Am J Respir Crit Care Med. 2013; 188: 647-656Crossref PubMed Scopus (270) Google Scholar Moreover, the coexistence of bronchiectasis with asthma or COPD should also be considered with severe disease.4Aksamit T.R. ÓDonnell A.E. Barker A. et al.Adult patients with bronchiectasis: a first look at the US Bronchiectasis Research Registry.Chest. 2017; 151: 982-992Abstract Full Text Full Text PDF PubMed Scopus (209) Google Scholar, 5Polverino E. Goeminne P.C. McDonnell M.J. et al.European Respiratory Society guidelines for the management of adult bronchiectasis.Eur Respir J. 2017; 50: 1700629Crossref PubMed Scopus (580) Google Scholar, 6Pasteur M.C. Bilton D. Hill A.T. British Thoracic Society guideline for non-CF bronchiectasis.Thorax. 2010; 65: i1-i58Crossref PubMed Scopus (505) Google Scholar, 7Martínez-García M.Á. Máiz L. Olveira C. et al.Spanish guidelines on treatment of bronchiectasis in adults.Arch Bronconeumol. 2018; 54: 88-98Crossref PubMed Scopus (10) Google Scholar, 15Gupta S. Siddiqui S. Haldar P. et al.Quantitative analysis of high-resolution computed tomography scans in severe asthma subphenotypes.Thorax. 2010; 65: 775-781Crossref PubMed Scopus (91) Google Scholar, 16Ni Y. Shi G. Yu Y. Hao J. Chen T. Song H. Clinical characteristics of patients with chronic obstructive pulmonary disease with comorbid bronchiectasis: a systemic review and meta-analysis.Int J Chron Obstruct Pulmon Dis. 2015; 10: 1465-1975Crossref PubMed Scopus (85) Google Scholar, 17Global Initiative for Asthma - GINA. www.ginasthma.org. Accessed January 11, 2018.Google Scholar, 18Vogelmeier C.F. Criner G.J. Martinez F.J. et al.Global strategy for the diagnosis, management, and prevention of chronic obstructive lung disease 2017 report. GOLD Executive Summary.Am J Respir Crit Care Med. 2017; 195: 557-582Crossref PubMed Scopus (1929) Google Scholar Additional research is critically needed to understand differences in phenotypic presentation, natural history, and unique responses to therapeutic interventions of patients with bronchiectasis, including specific etiologic subgroups and patients with an overlap of bronchiectasis with asthma or COPD. In conclusion, not all patients with chronic airway disease have asthma or COPD. A considerable proportion of patients may more accurately have a diagnosis of bronchiectasis, or possibly an overlap combination of bronchiectasis with asthma or COPD. Considering that bronchiectasis may represent the third most common etiology of chronic airway disease, it is of key importance that clinicians and clinical researchers for the purpose of best care and clinical trials, respectively, remain vigilant in establishing accurate diagnoses of specific airway diseases. Optimal attention to establishing correct airway diagnoses will likely lead to improved therapies and interventions, and improve the quality of life and prognosis of patients with bronchiectasis.

Bronchiectasis and Chronic Airway Disease