title: Risk of serious asthma exacerbations associated with long-acting beta agonists among patients with asthma: a retrospective cohort study.
abstract: BACKGROUND
  After the Serevent Nationwide Surveillance clinical trial, controversy has surrounded the safety of long-acting beta agonists (LABAs).
  
  
  OBJECTIVE
  Examine the association between LABAs and severe asthma exacerbations (SAEs).
  
  
  METHODS
  From a multistate Medicaid database, for the years 2002-2007, a total of 940,449 patients (age <40) with asthma were selected and divided into a cohort with newly-diagnosed asthma and one with pre-existing asthma. SAEs included asthma-related emergency department (ED) visits, hospitalizations, and intubations. Patients' asthma severity was determined based on medication regimen as suggested by the 2002 National Asthma Guidelines. Specific use of inhaled corticosteroids (ICSs), LABAs, ICS/LABA combination drugs, short-acting beta agonists (SABAs), and other drugs was tracked. Cox proportional hazard regressions were estimated to assess the risk of SAEs associated with patient severity, drug use, and covariates.
  
  
  RESULTS
  Compared to patients taking a SABA only, estimated SAE hazard ratios for newly diagnosed and pre-existing-asthma patients were as follows: 0.63 (95% CI 0.58-0.69) and 0.74 (0.70-0.79) for patients on a LABA without ICS, and 0.79 (0.77-0.81) and 0.90 (0.87-0.92) for those on a LABA/ICS single inhaler. Although hazard ratios were estimated to be similar for ED visits, LABA use was found to be positively associated with hospitalizations and intubations. Other key risk factors (P < .0001) included being African American, an alcohol/substance use disorder, pregnancy, and obesity.
  
  
  CONCLUSIONS
  Relative to SABA-only therapy, LABA use is associated with a lower risk of ED visit. Certain patients with asthma, such as pregnant women and African Americans, are particularly vulnerable to SAE risk of all types.
authors.affiliation: University of Cincinnati Medical Center, Cincinnati, Ohio 45267-0004, USA. jeff.guo@uc.edu
authors.forename: Jeff J
authors.initials: JJ
authors.lastname: Guo
authors.forename: Katherine
authors.initials: K
authors.lastname: Tsai
authors.forename: Christina M L
authors.initials: CM
authors.lastname: Kelton
authors.forename: Boyang
authors.initials: B
authors.lastname: Bian
authors.forename: Patricia R
authors.initials: PR
authors.lastname: Wigle
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D058666:Adrenergic beta-2 Receptor Agonists / Q000008:administration & dosage* / Q000009:adverse effects; D000328:Adult; D000420:Albuterol / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage* / Q000009:adverse effects; D001249:Asthma / Q000188:drug therapy*; D002648:Child; D002675:Child, Preschool; D002986:Clinical Trials as Topic; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D000068299:Salmeterol Xinafoate; D014481:United States; D055815:Young Adult
chemical_list: D058666:Adrenergic beta-2 Receptor Agonists; D018927:Anti-Asthmatic Agents; D000068299:Salmeterol Xinafoate; D000420:Albuterol