title: Assessment of major comorbidities in adults with atopic dermatitis using the Charlson comorbidity index.
abstract: BACKGROUND
  There is a growing interest in comorbidities of adults with atopic dermatitis (AD).
  
  
  OBJECTIVE
  To examine the burden of comorbidities in adult patients with AD using the Charlson comorbidity index (CCI) in nationwide registries.
  
  
  METHODS
  All Danish patients ≥18 years on January 1, 2012 with AD diagnosed by a hospital dermatologist were included. Patients were age-and sex-matched in a 1:4 ratio with general population controls. Severity was determined by systemic AD treatment and analyzed by conditional logistic regression.
  
  
  RESULTS
  In total, 10,738 adult patients with AD and 42,952 controls were analyzed. CCI score was significantly increased in smokers with AD compared with controls (0.41 vs 0.13, P < .001). Nonsmokers with AD had a similar CCI score as controls (0.09 vs 0.08, P = .12). In analyses restricted to patients with severe AD, a stronger difference in CCI score was observed for smokers (0.48 vs 0.14, P < .001) than for nonsmokers (0.10 vs 0.08, P = .01).
  
  
  CONCLUSIONS
  Observational studies do not establish cause and effect.
  
  
  CONCLUSIONS
  On the basis of nationwide data, the risk for major comorbidities was significantly increased in adult patients with AD compared with controls. The risk difference was predominantly found in patients with severe disease and among smokers.
authors.affiliation: Department of Dermatology and Allergy, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup, Denmark. Electronic address: jacob.p.thyssen@regionh.dk.
authors.forename: Jacob P
authors.initials: JP
authors.lastname: Thyssen
authors.affiliation: Department of Dermatology and Allergy, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.
authors.forename: Lone
authors.initials: L
authors.lastname: Skov
authors.affiliation: Department of Dermatology and Allergy, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.
authors.forename: Carsten R
authors.initials: CR
authors.lastname: Hamann
authors.affiliation: Department of Cardiology, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; The Danish Heart Foundation, Copenhagen, Denmark; The National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark.
authors.forename: Gunnar H
authors.initials: GH
authors.lastname: Gislason
authors.affiliation: Department of Dermatology and Allergy, Herlev and Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.
authors.forename: Alexander
authors.initials: A
authors.lastname: Egeberg
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015897:Comorbidity; D003876:Dermatitis, Atopic / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D055815:Young Adult
keywords: atopic dermatitis; comorbidity; epidemiology; risk; smoking