How many cats suffer with osteoarthritis (OA)? At what age do cats begin to show signs of OA? How many cats with OA do you see each week?
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The answers to these questions are likely to be higher than we think. We know that 90% of cats aged 12 years or over have radiographic signs of OA. However that does not necessarily correlate with clinical signs of pain – our diagnosis is a combination of a clinical and a radiographic diagnosis in order to definitively say that a cat has OA.
Which joints are most likely affected? In cats, it is elbows and hips. If one joint is affected, the contralateral joint is also likely to be affected. In one study by Slingerland et al (2011) they showed that lameness was not a regular feature of feline OA (13/100), there was no correlation with OA and body condition score and the prevalence increased with age.
This diagram depicts above our mainstays of care for cats with OA.
When it comes to considering which analgesics to use in feline OA management, we can use the concept of an analgesic ladder to decide how to proceed.
The literature regarding treatment is well established and evidence from 2006 teaches us the benefits of using NSAIDs (meloxicam) to improve the signs associated with OA in our feline population. In this work Clarke & Bennett (2006) used behavioural signs consistent with pain as their outcome measures, and concluded that NSAID administration significantly improves mobility impairment in cats diagnosed with OA.
Outcome measures are key, not only to scientific work, but also to us on a day-to-day basis when we, along with the caregiver, are assessing the response to treatment. Clarke & Bennett observed the following behaviours at baseline and after 28 days of treatment;
Statistically significant improvements were documented in;
● Ability to jump (P < 0.001)
● Height of jump (P < 0.001)
● Lameness (P = 0.03)
● Stiff gait (P = 0.04)
● Activity level (P = 0.02)
Measures that did not improve significantly;
· Vocalises if handled
· Resents handling
· Aggressive if handled &
· Seeks seclusion
We should incorporate such measures into our daily practice and discuss these with our cat owners.
Such pain behaviours are termed Client Specific Outcome Measures (CSOMs) and have been incorporated into a number of feline analgesia studies (Lascelles et al 2007). In this study, cats with OA were evaluated using CSOMs of mobility and quality of life, as well as accelerometry as an objective measure. Cats were treated with either meloxicam or placebo. Accelerometer scores increased to a greater percentage in the treatment group compared to placebo. Mobility improved significantly compared to placebo and QoL was also improved in the cats in the meloxicam group.
In recent work examining the safety and efficacy of frunevetmab, an anti-nerve growth factor monoclonal antibody, CSOMs were the main outcome measure for the study (Gruen et al 2021). In this work, 182 cats received frunevetmab and 93 placebo. Treatment success was documented at days 28 and 56 using CSOMs and owner global assessment. Vet assessed joint pain was improved at days 56 and 84, but not day 28. This work is open access and is worth a read to understand the value of using frunevetmab in our feline OA cases. Our webinar on 'New options in feline OA' covers the detail you need on anti-NGF options.
Note on placebo! The placebo effect is well documented in feline analgesia studies. The reasons behind this are unclear and it is important that we understand that this factor is at play, especially when we are using treatments which have not been widely studied (Gruen et al 2017).
The topic of nutraceuticals has been recently reviewed by Barbeau-Gregoire et al (2022). This works highlights some suspicions that we have held for a while and the authors state;
‘A very marked non-effect of chondroitin-glucosamine nutraceuticals, leads us to recommend that the latter products should no longer be recommended for pain management in canine and feline osteoarthritis’
‘The terms “chondroprotective”, “structure-modulator” or “disease-modifying” do not yet apply to the therapeutic approaches available in pet OA’
‘This meta-analysis supports the use of omega-3 supplementation for the management of canine and feline OA’
Other studies in cats document benefits to the addition of fish oils to the diet of cats – and there is work in dogs documenting a positive effect of one type of green-lipped mussel extract supplement. Considering compliance in cats, a dietary option appears to be a positive step forwards. Our webinar on 'Adjuncts to chronic pain management' will bring you up to speed.
Moving up the pain ladder, we can look at three other options of analgesics for cats – amantadine, gabapentin and tramadol. Each of the studies in the literature all share common themes – small numbers of subjects, formulation potentially an issue (ie: tramadol is bitter tasting), and sedation as a potential adverse effect in cats. These studies are able to document positive benefits to each of these agents. What we really need are larger studies – especially in view of our understanding of the placebo effect.
Watch 'How to manage chronic pain in cats' to find out the detail on these studies.
Don't forget! If you purchase our Cat Pain Course, you receive access to all of the webinars mentioned in this pain update, for just £99. That's a total of 7 webinars for cat lovers. Buy here now.
The analgesic ladder and our multimodal quadrant are perfectly placed to facilitate a discussion in your practice on how to approach feline OA management as a team.
References
Barbeau-Grégoire M, Otis C, Cournoyer A, Moreau M, Lussier B, Troncy E. A 2022 Systematic Review and Meta-Analysis of Enriched Therapeutic Diets and Nutraceuticals in Canine and Feline Osteoarthritis. Int J Mol Sci. 2022 Sep 8;23(18):10384. doi: 10.3390/ijms231810384.
Clarke SP, Bennett D. Feline osteoarthritis: a prospective study of 28 cases. J Small Anim Pract. 2006 Aug;47(8):439-45. doi: 10.1111/j.1748-5827.2006.00143.x. PMID: 16911111.
Gruen, M.E et al 2017. Caregiver Placebo Effect in Analgesic Clinical Trials for Painful Cats with Naturally-Occurring Degenerative Joint Disease Vet Rec. 2017 May 13; 180(19): 473.
Gruen ME, Myers JAE, Tena JS, Becskei C, Cleaver DM, Lascelles BDX. Frunevetmab, a felinized anti-nerve growth factor monoclonal antibody, for the treatment of pain from osteoarthritis in cats. J Vet Intern Med. 2021 Nov;35(6):2752-2762. doi: 10.1111/jvim.16291.
Lascelles BD, Hansen BD, Roe S, DePuy V, Thomson A, Pierce CC, Smith ES, Rowinski E: Evaluation of client-specific outcome measures and activity monitoring to measure pain relief in cats with osteoarthritis. J Vet Int Med. 2007, 21 (3): 410-416. 10.1111/j.1939-1676.2007.tb02983.x.
Slingerland, H.A.W. et al (2011) Cross-sectional study of the prevalence and clinical features of osteoarthritis in 100 cats The Veterinary Journal, 187 (3) 304-309 https://doi.org/10.1016/j.tvjl.2009.12.014.
This post was written by Matt Gurney.
Matt sees referrals in the pain clinic at Anderson Moores Veterinary Specialists. You can also receive telemedicine advice from us here if you have a pain case where you need a helping hand.
Matt & Carl established Zero Pain Philosophy to provide educational resources & telemedicine to veterinary professionals enabling optimal management of pain.
Matt Gurney is an RCVS & European Specialist in Veterinary Anaesthesia & Analgesia and works at Anderson Moores Veterinary Specialists. Matt is Past President of the European College of Veterinary Anaesthesia & Analgesia.
Carl Bradbrook is an RCVS & European Specialist in Veterinary Anaesthesia & Analgesia and is Past President of the Association of Veterinary Anaesthetists. Carl works at Anderson Moores Veterinary Specialists.
The intended audience for this pain update is veterinary professionals. This pain update is based on clinical experience and independent opinion.
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