title: Risk factors for COPD exacerbations in inhaled medication users: the COPDGene study biannual longitudinal follow-up prospective cohort.
abstract: BACKGROUND
  Despite inhaled medications that decrease exacerbation risk, some COPD patients experience frequent exacerbations. We determined prospective risk factors for exacerbations among subjects in the COPDGene Study taking inhaled medications.
  
  
  METHODS
  2113 COPD subjects were categorized into four medication use patterns: triple therapy with tiotropium (TIO) plus long-acting beta-agonist/inhaled-corticosteroid (ICS ± LABA), tiotropium alone, ICS ± LABA, and short-acting bronchodilators. Self-reported exacerbations were recorded in telephone and web-based longitudinal follow-up surveys. Associations with exacerbations were determined within each medication group using four separate logistic regression models. A head-to-head analysis compared exacerbation risk among subjects using tiotropium vs. ICS ± LABA.
  
  
  RESULTS
  In separate logistic regression models, the presence of gastroesophageal reflux, female gender, and higher scores on the St. George's Respiratory Questionnaire were significant predictors of exacerbator status within multiple medication groups (reflux: OR 1.62-2.75; female gender: OR 1.53 - OR 1.90; SGRQ: OR 1.02-1.03). Subjects taking either ICS ± LABA or tiotropium had similar baseline characteristics, allowing comparison between these two groups. In the head-to-head comparison, tiotropium users showed a trend towards lower rates of exacerbations (OR = 0.69 [95 % CI 0.45, 1.06], p = 0.09) compared with ICS ± LABA users, especially in subjects without comorbid asthma (OR = 0.56 [95% CI 0.31, 1.00], p = 0.05).
  
  
  CONCLUSIONS
  Each common COPD medication usage group showed unique risk factor patterns associated with increased risk of exacerbations, which may help clinicians identify subjects at risk. Compared to similar subjects using ICS ± LABA, those taking tiotropium showed a trend towards reduced exacerbation risk, especially in subjects without asthma.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT00608764, first received 1/28/2008.
authors: Channing Division of Network Medicine, Brigham and Women's Hospital, Harvard Medical School, 181 Longwood Avenue, Boston, MA, 02115, USA. rerbu@channing.harvard.edu.
authors: Robert
authors: R
authors: Busch
authors: Division of Pulmonary and Critical Care Medicine, University of Michigan, Ann Arbor, MI, USA. mrking@med.umich.edu.
authors: MeiLan K
authors: MK
authors: Han
authors: Department of Medicine, National Jewish Health, Denver, CO, USA. BowlerR@njhealth.org.
authors: Russell P
authors: RP
authors: Bowler
authors: Division of Pulmonary, Allergy, and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, AL, USA. mdrans99@uab.edu.
authors: Mark T
authors: MT
authors: Dransfield
authors: Division of Pulmonary, Allergy, and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, AL, USA. jmwells@uab.edu.
authors: J Michael
authors: JM
authors: Wells
authors: Department of Medicine, National Jewish Health, Denver, CO, USA. regane@njhealth.org.
authors: Elizabeth A
authors: EA
authors: Regan
authors: Channing Division of Network Medicine, Brigham and Women's Hospital, Harvard Medical School, 181 Longwood Avenue, Boston, MA, 02115, USA. craig.hersh@channing.harvard.edu.
authors: Craig P
authors: CP
authors: Hersh
mesh_terms: D000280:Administration, Inhalation; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use*; D000318:Adrenergic beta-Agonists / Q000627:therapeutic use*; D000368:Aged; D001249:Asthma / Q000453:epidemiology; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D015897:Comorbidity; D018450:Disease Progression; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D005764:Gastroesophageal Reflux / Q000453:epidemiology; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy* / Q000453:epidemiology; D012307:Risk Factors; D012737:Sex Factors; D000069447:Tiotropium Bromide / Q000627:therapeutic use*
chemical_list: D000305:Adrenal Cortex Hormones; D000318:Adrenergic beta-Agonists; D001993:Bronchodilator Agents; D000069447:Tiotropium Bromide