title: Preliminary development of a responder index for chronic low back pain.
abstract: OBJECTIVE
  One of the greatest obstacles to identifying the most effective therapy for chronic low back pain (CLBP) is the lack of standardized outcome measures for assessing treatment effect in clinical trials. The aim of the OMERACT Special Interest Group was to discuss the development and validation of a preliminary responder index in CLBP.
  
  
  METHODS
  Patient data from 5 clinical trials of celecoxib and valdecoxib use in CLBP were used to assess the reliability and validity of multiple items in the outcome domains of pain, functioning, and overall impression of health. Candidate preliminary responder indices were selected on the basis of effect size, high chi-square test values, and a placebo response rate < or = 25%.
  
  
  RESULTS
  Candidate indices comprised improvements in single outcome measures and combinations of improvements and/or avoidance of worsening in multiple measures. The preliminary choice for the responder index was at least 30% improvement in pain, with an improvement of at least 30% in patient global assessment and no worsening in function.
  
  
  CONCLUSIONS
  Further studies are needed to refine a responder index for CLBP trials that is clinically relevant, reliable, and easy to administer for standardizing assessments across clinical trials.
authors.affiliation: Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02465, USA. lsimon@bidmc.harvard.edu
authors.forename: Lee S
authors.initials: LS
authors.lastname: Simon
authors.forename: Christopher
authors.initials: C
authors.lastname: Evans
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Katz
authors.forename: Claire
authors.initials: C
authors.lastname: Bombardier
authors.forename: Christine
authors.initials: C
authors.lastname: West
authors.forename: Jeffery
authors.initials: J
authors.lastname: Robbins
authors.forename: Catherine
authors.initials: C
authors.lastname: Copley-Merriman
authors.forename: J
authors.initials: J
authors.lastname: Markman
authors.forename: John H
authors.initials: JH
authors.lastname: Coombs
mesh_terms: D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D000068579:Celecoxib; D002908:Chronic Disease; D002986:Clinical Trials as Topic; D017144:Focus Groups; D006305:Health Status Indicators; D006801:Humans; D007391:International Cooperation; D007555:Isoxazoles / Q000627:therapeutic use; D017116:Low Back Pain / Q000188:drug therapy* / Q000503:physiopathology / Q000523:psychology; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011720:Pyrazoles / Q000627:therapeutic use; D015203:Reproducibility of Results; D013449:Sulfonamides / Q000627:therapeutic use; D000096926:Benzenesulfonamides
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D000068579:Celecoxib; D007555:Isoxazoles; D011720:Pyrazoles; D013449:Sulfonamides; C406224:valdecoxib; D000096926:Benzenesulfonamides