title: Clinical predictors of exacerbation frequency in chronic obstructive pulmonary disease.
abstract: BACKGROUND
  Reduction of exacerbation frequency plays an increasingly important role in interventions in chronic obstructive pulmonary disease (COPD). To reduce this frequency efficiently, patients at risk for frequent exacerbations need to be identified.
  
  
  OBJECTIVE
  The objective of the study was to identify predictors for frequent exacerbations from multiple domains of COPD during a stable phase of the disease.
  
  
  METHODS
  Data of multiple domains of COPD were collected from 121 patients with moderate to severe COPD. Patients were divided into infrequent (<2 exacerbations per year) and frequent (≥2 exacerbations) exacerbators.
  
  
  RESULTS
  St. George's Respiratory Questionnaire (SGRQ) total score and a course of oral corticosteroid within 3 months prior to the study together predicted best whether patients would be infrequent or frequent exacerbators over the course of the next year. Each unit increase in total SGRQ score was associated with a 3% higher risk of being a frequent exacerbator [odds ratio (OR) = 1.03; 95% confidence interval (CI): 1.00-1.06; P = 0.047]. Patients who received a course of oral corticosteroids in the period of 3 months prior to the study had a three-fold increased risk of being a frequent exacerbator (OR = 3.17; 95% CI: 1.20-8.34; P = 0.02). Furthermore, we observed that a sizable number of patients switched from being a frequent to an infrequent exacerbator and vice versa.
  
  
  CONCLUSIONS
  Health-related quality of life and a course of oral corticosteroid in the past 3 months are the best predictors of future exacerbator status. The predictive value of the model is, however, still insufficient. Furthermore, our data suggest, in contrast to previous observations, that exacerbation frequency is not a constant feature.
authors.affiliation: Department of Pulmonary Medicine, Medisch Spectrum Twente, Enschede, the Netherlands. m.brusse-keizer@mst.nl
authors.forename: Marjolein
authors.initials: M
authors.lastname: Brusse-Keizer
authors.forename: Job
authors.initials: J
authors.lastname: van der Palen
authors.forename: Paul
authors.initials: P
authors.lastname: van der Valk
authors.forename: Ron
authors.initials: R
authors.lastname: Hendrix
authors.forename: Huib
authors.initials: H
authors.lastname: Kerstjens
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000368:Aged; D017079:Exercise Tolerance; D005260:Female; D005541:Forced Expiratory Volume; D005938:Glucocorticoids / Q000008:administration & dosage; D006304:Health Status; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy / Q000503:physiopathology*; D011788:Quality of Life; D013183:Sputum / Q000166:cytology / Q000382:microbiology; D011795:Surveys and Questionnaires; D014797:Vital Capacity
chemical_list: D005938:Glucocorticoids; D018836:Inflammation Mediators