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Open Access Research article

Clinical validity of outcome pain measures in naturally occurring canine osteoarthritis

Pascale Rialland12, Sylvain Bichot1, Maxim Moreau12, Martin Guillot12, Bertrand Lussier23, Dominique Gauvin12, Johanne Martel-Pelletier2, Jean-Pierre Pelletier2 and Eric Troncy12*

Author affiliations

1 Department of Biomedical Sciences, GREPAQ (Research Group in Animal Pharmacology of Quebec), St.-Hyacinthe (QC), J2S 7C6, Canada

2 Osteoarthritis Research Unit, University of Montreal Hospital Research Center (CRCHUM), Notre-Dame Hospital, Montreal (QC), H2L 4 M1, Canada

3 The Companion Animal Research Group; Faculty of Veterinary Medicine, Université de Montréal, St.-Hyacinthe (QC), J2S 7C6, Canada

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Citation and License

BMC Veterinary Research 2012, 8:162  doi:10.1186/1746-6148-8-162

Published: 10 September 2012

Abstract

Background

The conceptual validity of kinetic gait analysis and disability outcome assessment methods has guided their use in the assessment of pain caused by osteoarthritis (OA). No consensus on the best clinical methods for pain evaluation in canine OA exists, particularly, when evaluating treatments where a smaller treatment effect is anticipated than with pharmacological pain killers. This study thus aimed at determining the technical validity of some clinical endpoints on OA pain in dogs using the green-lipped mussel (GLM)-enriched diet.

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.

Results

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).

Conclusions

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).

Keywords:
Psychometrics; Dog osteoarthritis; Pain; Metrology; Kinetics; Accelerometry; Behavioral scales; Skin conductance