Clinical validity of outcome pain measures in naturally occurring canine osteoarthritis

Twenty-three adult dogs with clinical OA completed the prospective controlled study. All the dogs were fed a balanced diet over a 30-day control period followed by a GLM-enriched diet over a 60-day period. The kinetic gait analysis parameter (PVFBW, peak vertical force adjusted for body weight change), electrodermal activity (EDA), and a standardized multifactorial pain questionnaire (MFQ) were performed on day (D) 0 (inclusion), D30 (start) and D90 (end). The owners completed a client-specific outcome measures (CSOM) instrument twice a week. Motor activity (MA) was continuously recorded in seven dogs using telemetered accelerometric counts. We hypothesized that these methods would produce convergent results related to diet changes. A Type I error of 0.05 was adjusted to correct for the multiplicity of the primary clinical endpoints.Neither the EDA nor the MFQ were found reliable or could be validated. Changes in the PVFBW (Padj？=？0.0004), the CSOM (Padj？=？0.006) and the MA intensity (Padj？=？0.02) from D0 to D90 suggested an effect of diet(s). Only the PVFBW clearly increased after the GLM-diet (Padj？=？0.003). The CSOM exhibited a negative relationship with the PVFBW (P？=？0.02) and MA duration (P？=？0.02).The PVFBW exhibited the best technical validity for the characterization of the beneficial effect of a GLM-enriched diet. The CSOM and MA appeared less responsive following a GLM-diet, but these measures appeared complementary to gait analysis. Apparently, the CSOM provides the capacity to rely on pain OA assessment influenced by both lameness quantification (PVFBW) and physical functioning (MA).The prevalence of osteoarthritis (OA) in the canine population (20% of adult and 80% of the geriatric (> 8？years old) dogs in North America [1]) makes the disease a major cause of concern. The distortion between clinical and radiographic finding in dog OA is well recognized [2]. The symptomatic signs of OA are highly variable, related to pain and physical functioning, and tr