title: Relationship between FEV1 change and patient-reported outcomes in randomised trials of inhaled bronchodilators for stable COPD: a systematic review.
abstract: BACKGROUND
  Interactions between spirometry and patient-reported outcomes in COPD are not well understood. This systematic review and study-level analysis investigated the relationship between changes in FEV1 and changes in health status with bronchodilator therapy.
  
  
  METHODS
  Six databases (to October 2009) were searched to identify studies with long-acting bronchodilator therapy reporting FEV1 and health status, dyspnoea or exacerbations. Mean and standard deviations of treatment effects were extracted for each arm of each study. Relationships between changes in trough FEV1 and outcomes were assessed using correlations and random-effects regression modelling. The primary outcome was St George's Respiratory Questionnaire (SGRQ) total score.
  
  
  RESULTS
  Thirty-six studies (≥ 3 months) were included. Twenty-two studies (23,654 patients) with 49 treatment arms each contributing one data point provided SGRQ data. Change in trough FEV1 and change in SGRQ total score were negatively correlated (r = -0.46, p < 0.001); greater increases in FEV1 were associated with greater reductions (improvements) in SGRQ. The correlation strengthened with increasing study duration from 3 to 12 months. Regression modelling indicated that 100 mL increase in FEV1 (change at which patients are more likely to report improvement) was associated with a statistically significant reduction in SGRQ of 2.5 (95% CI 1.9, 3.1), while a clinically relevant SGRQ change (4.0) was associated with 160.6 (95% CI 129.0, 211.6) mL increase in FEV1. The association between change in FEV1 and other patient-reported outcomes was generally weak.
  
  
  CONCLUSIONS
  Our analyses indicate, at a study level, that improvement in mean trough FEV1 is associated with proportional improvements in health status.
authors.affiliation: Kleijnen Systematic Reviews Ltd,, York, UK. marie@systematic-reviews.com
authors.forename: Marie
authors.initials: M
authors.lastname: Westwood
authors.forename: Jean
authors.initials: J
authors.lastname: Bourbeau
authors.forename: Paul W
authors.initials: PW
authors.lastname: Jones
authors.forename: Annamaria
authors.initials: A
authors.lastname: Cerulli
authors.forename: Gorana
authors.initials: G
authors.lastname: Capkun-Niggli
authors.forename: Gill
authors.initials: G
authors.lastname: Worthy
mesh_terms: D000280:Administration, Inhalation; D000368:Aged; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D019317:Evidence-Based Medicine; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects*; D006304:Health Status; D006305:Health Status Indicators; D006801:Humans; D016014:Linear Models; D008168:Lung / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy* / Q000503:physiopathology; D016032:Randomized Controlled Trials as Topic; D013147:Spirometry; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D001993:Bronchodilator Agents