title: Describing and quantifying asthma comorbidity [corrected]: a population study.
abstract: BACKGROUND
  Asthma comorbidity has been correlated with poor asthma control, increased health services use, and decreased quality of life. Managing it improves these outcomes. Little is known about the amount of different types of comorbidity associated with asthma and how they vary by age.
  
  
  RESULTS
  The authors conducted a population study using health administrative data on all individuals living in Ontario, Canada (population 12 million). Types of asthma comorbidity were quantified by comparing physician health care claims between individuals with and without asthma in each of 14 major disease categories; results were adjusted for demographic factors and other comorbidity and stratified by age. Compared to those without asthma, individuals with asthma had higher rates of comorbidity in most major disease categories. Most notably, they had about fifty percent or more physician health care claims for respiratory disease (other than asthma) in all age groups; psychiatric disorders in individuals age four and under and age 18 to 44; perinatal disorders in individuals 17 years and under, and metabolic and immunity, and hematologic disorders in children four years and under.
  
  
  CONCLUSIONS
  Asthma appears to be associated with significant rates of various types of comorbidity that vary according to age. These results can be used to develop strategies to recognize and address asthma comorbidity to improve the overall health of individuals with asthma.
authors.affiliation: Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada. andrea.gershon@ices.on.ca
authors.forename: Andrea S
authors.initials: AS
authors.lastname: Gershon
authors.forename: Jun
authors.initials: J
authors.lastname: Guan
authors.forename: Chengning
authors.initials: C
authors.lastname: Wang
authors.forename: J Charles
authors.initials: JC
authors.lastname: Victor
authors.forename: Teresa
authors.initials: T
authors.lastname: To
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001249:Asthma / Q000453:epidemiology*; D015897:Comorbidity; D004194:Disease / Q000145:classification*; D005260:Female; D006801:Humans; D038801:International Classification of Diseases; D008297:Male; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D012307:Risk Factors