title: Power of treatment success definitions when the Canine Brief Pain Inventory is used to evaluate carprofen treatment for the control of pain and inflammation in dogs with osteoarthritis.
abstract: OBJECTIVE
  To determine the optimal method for use of the Canine Brief Pain Inventory (CBPI) to quantitate responses of dogs with osteoarthritis to treatment with carprofen or placebo.
  
  
  METHODS
  150 dogs with osteoarthritis.
  
  
  METHODS
  Data were analyzed from 2 studies with identical protocols in which owner-completed CBPIs were used. Treatment for each dog was classified as a success or failure by comparing the pain severity score (PSS) and pain interference score (PIS) on day 0 (baseline) with those on day 14. Treatment success or failure was defined on the basis of various combinations of reduction in the 2 scores when inclusion criteria were set as a PSS and PIS ≥ 1, 2, or 3 at baseline. Statistical analyses were performed to select the definition of treatment success that had the greatest statistical power to detect differences between carprofen and placebo treatments.
  
  
  RESULTS
  Defining treatment success as a reduction of ≥ 1 in PSS and ≥ 2 in PIS in each dog had consistently robust power. Power was 62.8% in the population that included only dogs with baseline scores ≥ 2 and 64.7% in the population that included only dogs with baseline scores ≥ 3.
  
  
  CONCLUSIONS
  The CBPI had robust statistical power to evaluate the treatment effect of carprofen in dogs with osteoarthritis when protocol success criteria were predefined as a reduction ≥ 1 in PIS and ≥ 2 in PSS. Results indicated the CBPI can be used as an outcome measure in clinical trials to evaluate new pain treatments when it is desirable to evaluate success in individual dogs rather than overall mean or median scores in a test population.
authors.affiliation: Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104.
authors.forename: Dorothy Cimino
authors.initials: DC
authors.lastname: Brown
authors.forename: Margie
authors.initials: M
authors.lastname: Bell
authors.forename: Linda
authors.initials: L
authors.lastname: Rhodes
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use*; D002227:Carbazoles / Q000627:therapeutic use*; D004283:Dog Diseases / Q000188:drug therapy*; D004285:Dogs; D004341:Drug Evaluation / Q000662:veterinary; D010003:Osteoarthritis / Q000150:complications / Q000188:drug therapy / Q000662:veterinary*; D010146:Pain / Q000188:drug therapy / Q000209:etiology / Q000662:veterinary*; D010147:Pain Measurement / Q000592:standards / Q000662:veterinary*; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D002227:Carbazoles; C007005:carprofen