title: Use of a preference-based measure of health (EQ-5D) in COPD and asthma.
abstract: BACKGROUND
  EQ-5D is a generic preference-based measure of health that can help to understand the impact of asthma and chronic obstructive pulmonary disease (COPD). The purpose of this paper was to synthesize literature on the validity and reliability of EQ-5D use in studies of asthma and COPD, and estimate EQ-5D utility scores associated with stage of disease.
  
  
  METHODS
  A structured search was conducted in EMBASE and MEDLINE (1988-2007) using keywords relevant to respiratory disease and EQ-5D. Original research studies in asthma or COPD that reported EQ-5D results and/or psychometric properties were included.
  
  
  RESULTS
  Studies that reported psychometric properties supported the construct validity, test-retest reliability, and responsiveness of EQ-5D in asthma (seven studies) and COPD (nine studies), although some evidence of ceiling effects were observed in asthma studies. In asthma studies that reported summary scores (n=11), EQ-5D index-based scores ranged from 0.42 (SD 0.30) to 0.93 (SD not reported). In COPD studies (n=8), scores ranged from 0.52 (SD 0.16) to 0.84 (SD 0.15). While few asthma studies reported scores by severity level, sufficient studies in COPD were available to calculate pooled mean utility scores according to GOLD stage: stage I=0.74 (0.62-0.87), stage II=0.74 (0.66-0.83), stage III=0.69 (0.60-0.78) and stage IV=0.61 (0.44-0.77) (most severe).
  
  
  CONCLUSIONS
  Evidence generally supported the validity and reliability of EQ-5D in asthma and COPD. Utility scores associated with COPD stage may be useful for modeling health outcomes in economic evaluations of treatments for COPD.
authors.affiliation: Center for Pharmacoeconomic Research, Department of Pharmacy Practice and Pharmacy Administration, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA. pickard1@uic.edu
authors.forename: A Simon
authors.initials: AS
authors.lastname: Pickard
authors.forename: Caitlyn
authors.initials: C
authors.lastname: Wilke
authors.forename: Eunmi
authors.initials: E
authors.lastname: Jung
authors.forename: Sneh
authors.initials: S
authors.lastname: Patel
authors.forename: Knut
authors.initials: K
authors.lastname: Stavem
authors.forename: Todd A
authors.initials: TA
authors.lastname: Lee
mesh_terms: D001249:Asthma / Q000503:physiopathology / Q000523:psychology*; D003625:Data Collection / Q000379:methods; D004185:Disability Evaluation; D006305:Health Status Indicators; D006801:Humans; D016247:Information Storage and Retrieval; D017060:Patient Satisfaction; D011594:Psychometrics; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology / Q000523:psychology*; D011788:Quality of Life