There are no validated systems for measuring pain in cats with osteoarthritis (OA). A study was designed to examine the use of owner-based assessments and activity monitors (AMs) to recognize behavioral changes associated with pain relief in cats with OA. Thirteen cats older than 10 years with no detectable systemic disease, painful arthritic joints, and owner-assessed decreases in activity, were studied. Client-specific outcomes measure (CSOM) forms were developed based on discussion with the owners about each cat's activity. Assessments were made at days 0, 7, 14, and 21 of the 3-week study. In weeks 2 and 3, all cats received an NSAID (0.1 mg/kg meloxicam on day 1, followed by 0.05 mg/kg daily for 4 days) and placebo for a 5-day period each in a randomized order. Owners completed a global quality-of-life assessment form after each treatment. An AM-a piezoelectric sensor that generates voltage when it undergoes a change in acceleration-was placed on a neck collar on the cats. The CSOM results showed that owners considered their cats to be more active on the NSAID compared with baseline and placebo and more active on placebo than at baseline. Activity counts from the AMs were significantly higher during the NSAID period than at baseline but not after placebo, and baseline activity counts were not significantly different from those of placebo. Global quality of life was significantly different for the 2 treatments, with the greatest improvement after NSAID administration. It was concluded that cat owners are able to detect changes in behavior associated with NSAID administration in cats with OA. In addition, objective data generated by accelerometer-based AMs can be used to validate subjective assessment systems for use in clinical studies of chronic feline pain.

COMMENTARY: Although the presence of pain in dogs with OA is reasonably well accepted, whether OA is painful in cats is still under discussion. Indeed, there are no medications that are currently approved for pain in cats with OA-something that may be attributed to the lack of validated techniques available for measuring pain (and relief of pain) in cats. Previous studies have shown that owners are able to assess chronic pain relief in dogs with OA. It therefore seems reasonable to assume that owners could do the same with their cats. Additional studies will be needed to devise a valid questionnaire for assessing chronic pain in cats. However, the study shows promise that objective activity monitoring can be used to do this, just as is done in human medicine for development of subjective rating scales.

Evaluation of client-specific outcome measures and activity monitoring to measure pain relief in cats with osteoarthritis. Lascelles BDX, Hansen BD, Roe S, et al. J VET INTERN MED 21:410-416, 2007.