title: Prevalence of common chronic respiratory diseases in drug  misusers: a cohort study.
abstract: BACKGROUND
  A randomised controlled trial of substance misuse indicated that many patients who use methadone have respiratory symptoms and/or are prescribed respiratory medications. There is little research in this area.
  
  
  OBJECTIVE
  To determine the prevalence of respiratory disease and prescriptions among drug misusers.
  
  
  METHODS
  This historical cohort study of drug misusers and matched controls analysed routinely collected primary care data. The prevalence of common chronic respiratory diseases, class and number of respiratory medications were examined.
  
  
  RESULTS
  The cohort of 18,570 patients (9,285 per group) was mostly male (64%, n=11,890) and aged 31-59 years (76%, n=14,060). After adjusting for age, gender, deprivation and smoking status, the results showed that more drug misusers than controls had a diagnosis of asthma or chronic obstructive pulmonary disease (17.1% vs. 10.9%; adjusted odds ratio (OR) 1.61, 95% confidence interval (CI) 1.46 to 1.77, and 2.4% vs. 0.8%; OR 1.86, 95% CI 1.42 to 2.44, respectively) and were prescribed more chronic respiratory medications: short-acting β(2)-agonists (16.4% vs. 7.9%; OR 2.00, 95% CI 1.80 to 2.22), long-acting β(2)-agonists (1% vs. 0.4%; OR 1.93, 95% CI 1.29 to 2.89), and inhaled corticosteroids (10.6% vs. 7.6%; OR 1.49, 95% CI 1.33 to 1.67). All differences were statistically significant (p<0.001).
  
  
  CONCLUSIONS
  Drug misusers have a significantly higher prevalence of respiratory diseases and respiratory prescriptions than matched controls. Further work is needed to determine the reasons for this.
authors.affiliation: Centre of Academic Primary Care, University of Aberdeen, Aberdeen, UK.
authors.forename: Frances
authors.initials: F
authors.lastname: Palmer
authors.forename: Mariesha
authors.initials: M
authors.lastname: Jaffray
authors.forename: Mandy A
authors.initials: MA
authors.lastname: Moffat
authors.forename: Catriona
authors.initials: C
authors.lastname: Matheson
authors.forename: David J
authors.initials: DJ
authors.lastname: McLernon
authors.forename: Alasdair
authors.initials: A
authors.lastname: Coutts
authors.forename: John
authors.initials: J
authors.lastname: Haughney
mesh_terms: D000305:Adrenal Cortex Hormones; D000328:Adult; D001249:Asthma / Q000150:complications; D002908:Chronic Disease; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications; D012140:Respiratory Tract Diseases / Q000150:complications* / Q000188:drug therapy / Q000453:epidemiology; D019966:Substance-Related Disorders / Q000150:complications*
chemical_list: D000305:Adrenal Cortex Hormones