Prevalence Data for OA in Companion Animals

B. Duncan X. Lascelles, BVSc, PhD, DACVS: You mentioned that there is sea change, Mark, and I think no one would disagree that that type of change needs to happen if the condition you’re talking about is important enough. How common is osteoarthritis in dogs? Let’s start with dogs. How common is osteoarthritis associated with clinical signs? And may you talk a little bit about the relationship between radiographs and clinical signs?

Mark Epstein, DVM, DABVP, CVPP: Well, there are some old data—some survey data. I think they’re maybe 20 years old by now, but it puts the figure at 20%, and you’ll see that still trotted out from time to time. And that’s just a rough question to veterinarians. How often do you see OA? It’s going to be far more than that 20%.

This disease starts in puppyhood for a lot of these animals. And for cats, we already said that 60% of all cats—90% if they’re over age 10—are going to have degenerative joint disease changes. So, to answer your question, Duncan, I would say those with referable clinical signs, either the client’s report that we pick up or that we can see on a physical exam, I would submit that the clients are more sensitive. In fact, caregiver placebo data suggest that the owners are more tuned into it than we are on our exams. It’s got to be at least one-third, and if I were to just say how many probably have osteoarthritis that are seeing me but that I’m not seeing, it has to be half.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: Let’s go down the line. So, maybe 40% to 50% of all dogs?

Mark Epstein, DVM, DABVP, CVPP: I’d say that.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: Sheilah?

Sheilah Robertson, BVMS, PhD, DACVAA, DACAW: I would say it’s over 30%, but I don’t know where my top limit would be. I was working, for a long time, as an anesthesiologist. I was seeing dogs that were coming in for perioperative care. And what we sometimes found is they got withdrawn from their nonsteroidal because of what we were doing. Then, we’d put them in a position on a surgical table for 4 hours. Then after, you realize that you’ve just unveiled a dog who has terrible osteoarthritis, but we weren’t really aware of it before. So, I think, sometimes, we reveal it by doing acute care. We could get into a whole other conversation about acute on top of chronic pain and what that can do to exacerbate and things. I’m not an expert on canine OA research, but I’d say, clinically, what I saw coming in for surgery was well over 30%.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: OK. Margaret, maybe you want to comment on cats?

Margaret Gruen, DVM, MVPH, PhD, DACVB: I can comment on cats, yes. I would say 40% to 50% of cats over age 10.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: We just heard Mark throw out a number of 60% to 90% of cats.

Mark Epstein, DVM, DABVP, CVPP: Have degenerative changes.

Margaret Gruen, DVM, MVPH, PhD, DACVB: Have radiographic signs. So, of those, maybe 40% or 50% have clinical signs of pain. This is one of those health areas where we really need some work done on the epidemiology of arthritic diseases in dogs, and that may be one way that we inform human health, as well.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: Bryan?

Bryan T. Torres, DVM, PhD, DACVS-SA, DACVSMR: For dogs, I think higher—at least 50%, if not more, of the adult dog population.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: Of the whole dog population?

Bryan T. Torres, DVM, PhD, DACVS-SA, DACVSMR: I think it has got to be.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: Detectable clinical signs?

Bryan T. Torres, DVM, PhD, DACVS-SA, DACVSMR: I think osteoarthritis is, probably, one of the most common, if not the most common, clinical conditions that veterinarians in private practice are treating on a daily basis. I think it has got to be. I would venture to believe that 50% or more of the patients, who a general practitioner sees on a daily basis, have arthritis.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: Margaret is suggesting 40% of all cats. I think all of us are agreeing that, certainly, the number is well over that 20% figure that’s thrown around.

Mark Epstein, DVM, DABVP, CVPP: I think that’s low.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: Maybe we are looking at a figure toward 50% of all dogs that show clinical signs associated with osteoarthritis?

Mark Epstein, DVM, DABVP, CVPP: Yes. It shouldn’t go unsaid, though, that for any given dog, and cat, eventually it’s 100%.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: That’s a good point, yes.

Bryan T. Torres, DVM, PhD, DACVS-SA, DACVSMR: One of the things that has changed, I think, in veterinary medicine over the past 10 to 20 years, is we’ve become very effective at treating and managing diseases. Our population is aging just like we are aging. And so, we will see it more and more. It will be more common because, as you said, we have these dogs who are living much longer lives and have a lot of comorbidities. We have to figure out how to manage them for that long with osteoarthritis. But I think as our population ages in the canine world and in the feline world, 20% in dogs has to be a low percentage at this point.

Margaret Gruen, DVM, MVPH, PhD, DACVB: And as our population gets heavier.

Bryan T. Torres, DVM, PhD, DACVS-SA, DACVSMR: Gets heavier as well.

Margaret Gruen, DVM, MVPH, PhD, DACVB: Yes, obesity.

Bryan T. Torres, DVM, PhD, DACVS-SA, DACVSMR: Kind of trending, as well, like the United States.

Sheilah Robertson, BVMS, PhD, DACVAA, DACAW: Yes. The latest data that I read are that 59% or 60% of all dogs are either overweight or obese. With cats, it’s pretty similar—it’s over 50%. We talk about obesity being a disease within itself. In inflammatory disease, we have OA. So, yes, an aging population that are also, probably, overweight is a challenge.

Mark Epstein, DVM, DABVP, CVPP: I’m going to echo Bryan. We see externs and we hire new grads, and they come out all energized. They’ve done a lot of critical care. They’ve been in the intensive care unit, and the sexy part of practice is the DKA (diabetic ketoacidosis) dog or the big dog or little dog.

Bryan T. Torres, DVM, PhD, DACVS-SA, DACVSMR: For some.

Mark Epstein, DVM, DABVP, CVPP: For the surgeons, not so much. But in my view, and experientially, my estimation is that this is the sexiest part of practice, really. This is chronic care because you are in the trenches with these folks helping to extend their quality of life and their length of life. And if you can take that dog or that cat and get it from age 15 to age 17, or age 17 to age 19, that, to me, is golden. That’s why it’s a very special part of practice. Even though it’s stretched out over a long, long period of time, it’s the most rewarding part, for me.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: And that goes back to something you said earlier, Sheilah—that osteoarthritis kills. It is a very common reason for euthanasia.

Mark Epstein, DVM, DABVP, CVPP: Two-thirds of them, in that lifelong Labrador study you were talking about with weight optimization, were euthanized because of mobility and orthopedic issues.

Sheilah Robertson, BVMS, PhD, DACVAA, DACAW: And if you think about how many other specific populations are going to be affected by this in a very dramatic way—ie, our military working dogs, our seeing-eye dogs, the working dogs—it’s a devastating disease for the person and their job. It’s their job. They’re not a pet. So, I think there’s a huge area, there, that we need to think about. Also, you don’t need to be a pain expert or an orthopedic expert. I think what a lot of us are becoming, in practice, are geriatricians. There are geriatricians in human medicine. They take care of a special population, and we’re certainly moving into that older population even though arthritis is not just an old-age disease. I think we’ve cleared that up today, but our client population is changing.

B. Duncan X. Lascelles, BVSc, PhD, DACVS: The impact of OA can be devastating and can result in euthanasia. Yet, we all agree that OA is very common. So, I think we could all agree that, as a profession, we should work to incorporate these assessment tools—ie, the questionnaires, the activity monitoring, health-related quality of life? We should incorporate them into our practices?

Sheilah Robertson, BVMS, PhD, DACVAA, DACAW: Yes. I also think a lot of people routinely, on a visit, are going to look at body condition score. But it’s really important to be thinking about muscle condition. We’ve touched a little bit on sarcopenia. It is an aging disease that we know a lot about in humans and less so in animals—regarding what type of muscle deteriorates with age and how we can help that. So, I think body condition scoring—because of the obesity issue—and also guidelines on how we assess muscle strength, muscle size, and those things are really important as well.