title: Inhaled corticosteroids and risk of recurrent pneumonia: a population-based, nested case-control study.
abstract: BACKGROUND
  Studies have suggested an increased risk of pneumonia with inhaled corticosteroid (ICS) use, although this association is inconsistent. We evaluated the risk of recurrent pneumonia associated with ICS use in a high-risk population of individuals who survived an episode of pneumonia.
  
  
  METHODS
  Clinical and 5-year follow-up data were collected on all adults aged ≥ 65 years with pneumonia over a period of 2 years. Using a nested case-control design, first cases (patients with recurrent pneumonia ≥ 30 days after initial episode) and then controls (free of pneumonia and matched on age, sex, and chronic obstructive pulmonary disease [COPD]) were identified. ICS use was classified as never, past (remote, only before initial pneumonia), or current. Our primary outcome measure was recurrent pneumonia assessed using conditional multivariate logistic regression after adjustment of demographics and clinical data.
  
  
  RESULTS
  During 5 years of follow-up, 653 recurrent pneumonia cases were matched with 6244 controls; mean age was 79 (SD, 8) years, 3577 (52%) were male, 2652 (38%) had COPD, and 2294 (33%) ever used ICS. Overall, 123 of 870 (14%) current ICS users had recurrent pneumonia compared to 395 of 4603 (9%) never-users (adjusted odds ratio, 1.90; 95% confidence interval, 1.45-2.50; P < .001; number need to harm = 20). Conversely, there was no association between past (remote) use of ICS and pneumonia: 9% of past users versus 9% never-users (P = .36).
  
  
  CONCLUSIONS
  ICS use was associated with a 90% relative increase in the risk of recurrent pneumonia among high-risk pneumonia survivors. This should be considered when prescribing ICS and when deciding which patients might need more intensive follow-up.
authors.affiliation: Department of Public Health Sciences, School of Public Health.
authors.forename: Dean T
authors.initials: DT
authors.lastname: Eurich
authors.forename: Colin
authors.initials: C
authors.lastname: Lee
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Marrie
authors.forename: Sumit R
authors.initials: SR
authors.lastname: Majumdar
mesh_terms: D000280:Administration, Inhalation; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage* / Q000009:adverse effects; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D017714:Community-Acquired Infections / Q000139:chemically induced / Q000453:epidemiology; D005260:Female; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000188:drug therapy; D008297:Male; D015999:Multivariate Analysis; D011014:Pneumonia / Q000139:chemically induced / Q000453:epidemiology*; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D000305:Adrenal Cortex Hormones
keywords: ICS; corticosteroids; elderly; pneumonia