title: Bronchiectasis as a Comorbidity of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis.
abstract: BACKGROUND
  Bronchiectasis revealed by chest computed tomography in COPD patients and its comorbid effect on prognosis have not been addressed by large-sized studies. Understanding the presence of bronchiectasis in COPD is important for future intervention and preventing disease progression.
  
  
  METHODS
  Observational studies were identified from electronic literature searches in Cochrane library, PubMed, ScienceDirect databases, American Thoracic Society and European Respiratory Society meeting abstracts. A systematic review and meta-analysis of studies was performed to summarize the factors associated with bronchiectasis in COPD patients. Primary outcomes included the risks for exacerbation frequency, isolation of a potentially pathogenic microorganism, severe airway obstruction and mortality. Odds ratios (ORs) were pooled by random effects models.
  
  
  RESULTS
  Fourteen observational studies were eligible for the study. Compared with COPD without bronchiectasis, comorbid bronchiectasis in COPD increased the risk of exacerbation (1.97, 95% CI, 1.29-3.00), isolation of a potentially pathogenic microorganism (4.11, 95%CI, 2.16-7.82), severe airway obstruction (1.31, 95% CI, 1.09-1.58) and mortality (1.96, 95% CI, 1.04-3.70).
  
  
  CONCLUSIONS
  The presence of bronchiectasis in patients with COPD was associated with exacerbation frequency, isolation of a potentially pathogenic microorganism, severe airway obstruction and mortality.
authors.affiliation: Department of Respiratory Medicine and Department of Emergency, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China.
authors.forename: Qingxia
authors.initials: Q
authors.lastname: Du
authors.affiliation: Department of Respiratory Medicine and Department of Emergency, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Jin
authors.affiliation: Department of Respiratory Medicine and Department of Emergency, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Respiratory Medicine and Department of Emergency, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China.|Department of Respiratory and Critical Care Medicine, Peking University Third Hospital, Beijing, 100191 China.
authors.forename: Yongchang
authors.initials: Y
authors.lastname: Sun
mesh_terms: D000368:Aged; D001987:Bronchiectasis / Q000150:complications* / Q000000981:diagnostic imaging; D015331:Cohort Studies; D006801:Humans; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications*; D014057:Tomography, X-Ray Computed