title: Overlap of asthma and chronic obstructive pulmonary disease.
abstract: OBJECTIVE
  Asthma and chronic obstructive pulmonary disease (COPD) are both defined by the presence of airflow obstruction, but they present distinguishing differences in terms of both risk factors and clinical phenotypes. Yet it is quite common in the clinical setting to observe patients with asthma showing COPD-like phenotypes, and vice versa, making it a priority to search for optimal prevention, treatment, and management strategies for these cases of coexisting lung obstructive diseases.
  
  
  RESULTS
  Recent studies have provided further evidence of strong epidemiologic and clinical links between asthma and COPD. Adult subjects with active asthma are as much as 12 times more likely to acquire COPD over time than subjects with no active asthma. Signs identifying patients with asthma predisposed to developing COPD may already be present at the early stages of the disease, a finding with potential implications for prevention of COPD. In addition to spirometry and other pulmonary function tests (such as measurements of residual volume and diffusing capacity of the lung for carbon monoxide), recent evidence suggests that the assessment of type and degree of airway remodeling and the evaluation of inflammatory markers might prove useful in the future to characterize phenotypically patients with coexisting asthma and COPD.
  
  
  CONCLUSIONS
  The nature of the association between asthma and COPD remains unclear and open to discussion. Further research is required to develop effective management algorithms for patients with multiple obstructive lung diseases, determine to what extent early treatment and optimal management of asthma may protect against progression into COPD, and identify genetic markers of individual susceptibility to specific lung disease phenotypes and pharmacologic treatments.
authors.affiliation: Arizona Respiratory Center and Department of Medicine, College of Medicine, University of Arizona, Tucson, AZ 85724, USA. sguerra@arc.arizona.edu
authors.forename: Stefano
authors.initials: S
authors.lastname: Guerra
mesh_terms: D001249:Asthma / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D003937:Diagnosis, Differential; D006801:Humans; D007249:Inflammation / Q000473:pathology / Q000503:physiopathology; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D012129:Respiratory Function Tests; D012137:Respiratory System / Q000473:pathology / Q000503:physiopathology; D012307:Risk Factors