title: Correlation of measures of pain, function, and overall response: results pooled from two identical studies of etoricoxib in chronic low back pain.
abstract: METHODS
  Assessment of correlation of measures of low back pain (LBP) using data pooled from 2 identical studies.
  
  
  OBJECTIVE
  To assess the relative responsiveness of and correlation between various measures of LBP, including the Roland-Morris Disability Questionnaire (RMDQ), the LBP intensity (LBPI) visual analog scale (VAS), and patient's global assessment of response to therapy (PGART).
  
  
  BACKGROUND
  Several tools are available to measure pain, functional limitation, and response to therapy for LBP. Studies have shown varying degrees of responsiveness and correlation.
  
  
  METHODS
  This was a pooled subgroup analysis of patients with chronic LBP from 2 identical studies comparing etoricoxib 60 mg, 90 mg, and placebo. LBP was assessed by the time-weighted average change from baseline over 12 weeks as measured by RMDQ, LBPI VAS, and PGART. Correlation was calculated using Pearson's correlation coefficient.
  
  
  RESULTS
  The correlation (r) between LBPI and RMDQ changes ranged from 0.657 and 0.703; correlations between LBPI and PGART changes ranged from 0.677 and 0.738. Cutpoints separating responders from nonresponders for all 3 measures fell near the 66.7th percentile of response and were consistent with minimal clinically significant changes identified in the literature.
  
  
  CONCLUSIONS
  In this study, the RMDQ, LBPI VAS, and PGART showed a high degree of correlation in measuring response to therapy in LBP, suggesting clinicians may be able to simplify assessments.
authors.affiliation: Miami Research Associates, Miami, Florida, USA.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Sheldon
authors.forename: Steven R
authors.initials: SR
authors.lastname: Bird
authors.forename: Steven S
authors.initials: SS
authors.lastname: Smugar
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Tershakovec
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002908:Chronic Disease; D016861:Cyclooxygenase Inhibitors / Q000008:administration & dosage*; D004185:Disability Evaluation; D000077613:Etoricoxib; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis* / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D011725:Pyridines / Q000008:administration & dosage*; D012372:ROC Curve; D013450:Sulfones / Q000008:administration & dosage*; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
chemical_list: D016861:Cyclooxygenase Inhibitors; D011725:Pyridines; D013450:Sulfones; D000077613:Etoricoxib