title: Reliability and validity of a visual analogue scale used by owners to measure chronic pain attributable to osteoarthritis in their dogs.
abstract: OBJECTIVE
  To assess validity and reliability for a visual analogue scale (VAS) used by owners to measure chronic pain in their osteoarthritic dogs.
  
  
  METHODS
  68, 61, and 34 owners who completed a questionnaire.
  
  
  METHODS
  Owners answered questionnaires at 5 time points. Criterion validity of the VAS was evaluated for all dogs in the intended-to-treat population by correlating scores for the VAS with scores for the validated Helsinki Chronic Pain Index (HCPI) and a relative quality-of-life scale. Intraclass correlation was used to assess repeatability of the pain VAS at 2 baseline evaluations. To determine sensitivity to change and face validity of the VAS, 2 blinded, randomized control groups (17 dogs receiving carprofen and 17 receiving a placebo) were analyzed over time.
  
  
  RESULTS
  Significant correlations existed between the VAS score and the quality-of-life scale and HCPI scores. Intraclass coefficient (r = 0.72; 95% confidence interval, 0.57 to 0.82) for the VAS indicated good repeatability. In the carprofen and placebo groups, there was poor correlation between the 2 pain evaluation methods (VAS and HCPI items) at the baseline evaluation, but the correlation improved in the carprofen group over time. No correlation was detected for the placebo group over time.
  
  
  CONCLUSIONS
  Although valid and reliable, the pain VAS was a poor tool for untrained owners because of poor face validity (ie, owners could not recognize their dogs' behavior as signs of pain). Only after owners had seen pain diminish and then return (after starting and discontinuing NSAID use) did the VAS have face validity.
authors.affiliation: Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, 00014 Helsinki, Finland. anna.hielmbjorkman@helsinki.fi
authors.forename: Anna K
authors.initials: AK
authors.lastname: Hielm-Björkman
authors.forename: Amy S
authors.initials: AS
authors.lastname: Kapatkin
authors.forename: Hannu J
authors.initials: HJ
authors.lastname: Rita
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage; D002227:Carbazoles / Q000008:administration & dosage; D002908:Chronic Disease / Q000188:drug therapy; D004283:Dog Diseases / Q000175:diagnosis* / Q000188:drug therapy; D004285:Dogs; D005260:Female; D008297:Male; D010003:Osteoarthritis / Q000175:diagnosis / Q000188:drug therapy / Q000662:veterinary*; D010146:Pain / Q000175:diagnosis / Q000188:drug therapy / Q000662:veterinary*; D010147:Pain Measurement / Q000379:methods / Q000592:standards / Q000662:veterinary*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D002227:Carbazoles; C007005:carprofen