title: Non-emphysematous chronic obstructive pulmonary disease is associated with diabetes mellitus.
abstract: BACKGROUND
  Chronic obstructive pulmonary disease (COPD) has been classically divided into blue bloaters and pink puffers. The utility of these clinical subtypes is unclear. However, the broader distinction between airway-predominant and emphysema-predominant COPD may be clinically relevant. The objective was to define clinical features of emphysema-predominant and non-emphysematous COPD patients.
  
  
  METHODS
  Current and former smokers from the Genetic Epidemiology of COPD Study (COPDGene) had chest computed tomography (CT) scans with quantitative image analysis. Emphysema-predominant COPD was defined by low attenuation area at -950 Hounsfield Units (LAA-950) ≥10%. Non-emphysematous COPD was defined by airflow obstruction with minimal to no emphysema (LAA-950 < 5%).
  
  
  RESULTS
  Out of 4197 COPD subjects, 1687 were classified as emphysema-predominant and 1817 as non-emphysematous; 693 had LAA-950 between 5-10% and were not categorized. Subjects with emphysema-predominant COPD were older (65.6 vs 60.6 years, p < 0.0001) with more severe COPD based on airflow obstruction (FEV1 44.5 vs 68.4%, p < 0.0001), greater exercise limitation (6-minute walk distance 1138 vs 1331 ft, p < 0.0001) and reduced quality of life (St. George's Respiratory Questionnaire score 43 vs 31, p < 0.0001). Self-reported diabetes was more frequent in non-emphysematous COPD (OR 2.13, p < 0.001), which was also confirmed using a strict definition of diabetes based on medication use. The association between diabetes and non-emphysematous COPD was replicated in the ECLIPSE study.
  
  
  CONCLUSIONS
  Non-emphysematous COPD, defined by airflow obstruction with a paucity of emphysema on chest CT scan, is associated with an increased risk of diabetes. COPD patients without emphysema may warrant closer monitoring for diabetes, hypertension, and hyperlipidemia and vice versa.
  
  
  BACKGROUND
  Clinicaltrials.gov identifiers: COPDGene NCT00608764, ECLIPSE NCT00292552.
authors.affiliation: Channing Division of Network Medicine, Boston, MA, USA. craig.hersh@channing.harvard.edu.
authors.forename: Craig P
authors.initials: CP
authors.lastname: Hersh
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Make
authors.forename: David A
authors.initials: DA
authors.lastname: Lynch
authors.forename: R Graham
authors.initials: RG
authors.lastname: Barr
authors.forename: Russell P
authors.initials: RP
authors.lastname: Bowler
authors.forename: Peter M A
authors.initials: PM
authors.lastname: Calverley
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Castaldi
authors.forename: Michael H
authors.initials: MH
authors.lastname: Cho
authors.forename: Harvey O
authors.initials: HO
authors.lastname: Coxson
authors.forename: Dawn L
authors.initials: DL
authors.lastname: DeMeo
authors.forename: Marilyn G
authors.initials: MG
authors.lastname: Foreman
authors.forename: MeiLan K
authors.initials: MK
authors.lastname: Han
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Harshfield
authors.forename: John E
authors.initials: JE
authors.lastname: Hokanson
authors.forename: Sharon
authors.initials: S
authors.lastname: Lutz
authors.forename: Joe W
authors.initials: JW
authors.lastname: Ramsdell
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Regan
authors.forename: Stephen I
authors.initials: SI
authors.lastname: Rennard
authors.forename: Joyce D
authors.initials: JD
authors.lastname: Schroeder
authors.forename: Frank C
authors.initials: FC
authors.lastname: Sciurba
authors.forename: Robert M
authors.initials: RM
authors.lastname: Steiner
authors.forename: Ruth
authors.initials: R
authors.lastname: Tal-Singer
authors.forename: Edwin
authors.initials: E
authors.lastname: van Beek
authors.forename: Edwin K
authors.initials: EK
authors.lastname: Silverman
authors.forename: James D
authors.initials: JD
authors.lastname: Crapo
mesh_terms: D000367:Age Factors; D000368:Aged; D015897:Comorbidity; D003920:Diabetes Mellitus / Q000453:epidemiology*; D017079:Exercise Tolerance; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging / Q000453:epidemiology*; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging / Q000453:epidemiology*; D011788:Quality of Life; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed; D014481:United States / Q000453:epidemiology