You’re listening to ReachMD. This episode of Living Rheum, titled “Assessing PsA Disease Activity in Clinical Practice” is sponsored by Novartis US Clinical Development and Medical Affairs. The host and speaker have been compensated for their time. This program is intended for health care professionals. Here’s your host, Dr Ethan Craig.
So, as tricky as it can be to diagnose psoriatic arthritis, or PsA for short, sometimes monitoring clinical features over time presents an even trickier challenge. It requires monitoring of multiple domains of disease, which may not always be amenable to physical exam. In particular, assessment of enthesitis and axial involvement often rely on patient reports rather than findings on clinical exam. And clinical exam findings can be nonspecific, and that can really make monitoring response to therapy a challenge.
So, this is ReachMD, and I'm Dr Ethan Craig. Joining me to discuss this important topic of monitoring disease activity in psoriatic arthritis is Dr Alexis Ogdie. Dr Ogdie is an Associate Professor of Medicine and Epidemiology in the Perelman School of Medicine and is the Director of the Penn Psoriatic Arthritis and Spondyloarthritis Program at the University of Pennsylvania. Dr Ogdie, thank you for being here today.
Thanks so much for having me.
So, let's maybe begin by establishing the different domains that we think of in psoriatic arthritis. Dr Ogdie, what domains do you address when you're seeing patients with PsA?
Yeah, I mean, I guess if you think about RA and PsA, RA seems relatively easy to monitor because you literally do your 28-joint count, you might check a CRP, you get a patient-reported outcome, and you're kind of done. With PsA, it's a little more complicated because of, the different tissues that can be involved. So not only do you have the peripheral arthritis, but you can also have enthesitis, or inflammation where tendon ligament or joint capsule inserts onto the bone. You can have axial disease, which is axial spondyloarthritis, as a part of psoriatic arthritis, you have dactylitis or swelling of an entire digit from the base to the top, and then you have the psoriasis as well. And the tricky piece is that these don't always all respond to therapy in the same way. And it's important to know what domains are active and in order to choose the best therapy for the given patient.
Dr Ogdie, what disease activity measures do you use in practice for patients with psoriatic arthritis? And do you recommend any of these disease activity scores to be used in, for monitoring in clinical practice?
Yeah, so there's a variety of different ways in which to monitor these patients. One is through patient-reported outcomes, which I think is really important, and I'll come back to that. And the second is through general disease activity measures that are the things that we do in practice. For example, joint counts, and so on. So, let's start with PROs, and we'll come back to the joint counts.
In terms of PROs, there are a variety of different options out there for monitoring psoriatic arthritis. One of the most commonly used in the United States is the RAPID3. So, I think many rheumatologists are familiar with this patient-reported outcome. It’s the Routine Assessment of Patient Index Data 3, or RAPID3. It is a combination of 10 items about the patient's physical function, a patient global assessment, and a patient pain assessment, as well as 3 unscored items that assess sleep, depression, and anxiety. So, this is really helpful information in general when we're taking care of the patient, even just to look through that, as well as to track what's happening over time. Our patients actually get this RAPID3 in their little inbox in their app about a week before our visit, and then they fill that out so that when I come in the room, I have its general sense of how they're doing, and especially relative to where they were the last time, I saw them. So, I find this questionnaire very helpful. And the patient pain and patient global assessment can be used independently in the scores we're going to talk about next. But first, before we move to the disease activity scores, let's talk about some other options for PROs, if you don't want to do the RAPID3.
So increasingly common in the United States, patients are using PROMIS measures. These are Patient-Reported Outcome Measurement Information System, long term, this is a, set of questionnaires developed by the NIH to help us measure patient outcomes better. And these work across disease states. So, you can use these for any disease in your clinic or anyone in the general population, and their population normed scores. So, the scores actually have a great you understand what they mean, because 50 is normal, up to 100 is higher than normal, down to zero is lower than normal. So, they're fairly easy to interpret. And they include things like sleep, depression, anxiety, fatigue, physical function, and pain. So, a lot of those key things that we want to know about.
Then there are also disease-specific patient-reported outcomes. These include the BASDAI and the PsAID. So, the BASDAI is the Bath Ankylosing Spondylitis Disease Activity Index. This is again well known to many rheumatologists as the way we follow ankylosing spondylitis. But one of the nice things about this measure is that you can also use it in psoriatic arthritis. And it does tend to work fairly well there as well. There's only one question actually about the spine. But you'd have to be, you know, giving this to just the PsA and axSpA patients; whereas for the other two questionnaires I mentioned, you can use them more broadly in your clinic.
And then finally, there's the most specific, the Psoriatic Arthritis Impact of Disease questionnaire or the PsAID. So, the PsAID is 12 items, and it includes these very, nice, 12 questions about, for example, the skin, their physical function, their social function, depression, anxiety, embarrassment, and other things you want to know about. So, it's nice because the items make sense individually, and so you can kind of just scan down and take a look at what's going on with the individual patient.
So, a variety of different options. As mentioned, we use RAPID3 right now. We've been considering the PROMIS measures instead of RAPID3. But it's nice to be able to track people over time, with inflammatory arthritis.
So now, we talked about patient-reported outcomes, what are the different assessments that we as clinicians should be doing? Well, at baseline, we should be doing a joint, or in general, at every visit, we should be doing a joint count. So, in rheumatoid arthritis, they use a 28-joint count. In psoriatic arthritis, we use a 66, 68 joint count. So, we assess 66 swollen joints and 68 tender joints, because the hips can't really observe swelling, so they don't count in the swollen joint count. So, after you've done that, then we also do an enthesitis examination. And we'll talk more about that shortly. But either the Leeds Enthesitis Index or the SPARCC index are the ones that we use. And then we do a skin assessment. So that's, the body surface area is what we generally follow in clinical practice. The body surface area is just the number of palms of psoriasis a patient has on their body.
So, once we have that information, we can then, calculate two different scores. One is the Minimal Disease Activity index, or MDA. So, this is 7 different items that include the swollen and tender joint count, the patient global, the patient pain, the patient's function, all of, what, all 3 of those you could get from the RAPID3. You can also use the PsAID. And then also the enthesitis index and the psoriasis. And so, there's kind of a bottom number for each of those. For example, in 1 or less swollen joints, and so on. So that if your patient is getting to 5 of those, they have a much higher likelihood of having good quality of life, less progression, and so on. So that's a good place to be.
The other option that's slightly simpler is called the Clinical Disease Activity in Psoriatic Arthritis or the cDAPSA. This is just the sum of the swollen and tender joint count and the patient pain and the patient global. So similar to a CDAI, and rheumatoid arthritis. And this, again, is very easy to use in clinical practice. We have a little smart set that calculates this for us.
So, a variety of different things you can do. I suggest finding something that works for you, that works across your practice. And then including that in your template so that you would do the same thing every time. And that helps us monitor how the patient is doing over time.
And if we zero in then on scores for monitoring enthesitis, do you prefer one scoring index over the other? And how do you approach these in patients with comorbid central pain sensitization?
So, there's a variety of different enthesitis indices. The ones that I tend to use are either the SPARCC, which is the, Spondyloarthritis Research Consortium of Canada enthesitis index, or the Leeds Enthesitis index. These are pretty easy and they're peripheral. So, in PsA, enthesitis tends to be more peripheral, whereas the axSpA, enthesitis index, the Maastricht, or the MASES, index is actually just more spine focused, so it's a lot of points in that are not nearly as relevant to the patient with PsA.
So, the SPARCC index includes places like the shoulder, humeral head insertion, lateral medial epicondyle, trochanteric bursa, over the top of the knee, the patellar tendon insertion, the Achilles. And then the LEI includes the plantar sorry, the Achilles, the knee, and that lateral epicondyle. So, it's shorter, the LEI is only 3 on each side, so a total of 6 entheses. So, it can be done really quickly.
I don't really use any of the ultrasound-based scores. There are new ultrasound-based, enthesitis scores. Those are really mostly for studies.
And then how do you address this in patients with central sensitization or fibromyalgia? That's really hard. That - really the, entheses are kind of overlaying those tender points and so a lot of patients are going to be tender. I think it gives you information still because you know the patient's got widespread tenderness and their, central sensitization needs to be addressed and/or fibromyalgia. So, you know, talking about that with the patient can go a long way, and maybe even treating with, for example, some of the therapies that are used for depression or for central pain can be really helpful in improving the patient's quality of life. So, it gives you information, but it doesn't tell you that there's actual inflammation there.
So, Dr Ogdie, if we shift our focus then over to the role of labs and imaging in PsA, a specific challenge can be differentiating between disease manifestations, especially enthesitis or axial disease versus mechanical pathologies coexisting with disease. So, if we focus then especially on the enthesis, how accurate is our imaging in differentiating between enthesitis and things like tendinopathies?
That really is one of the hardest things we do in clinic is try to differentiate between what's inflammatory and what's not inflammatory, and that happens even within our PsA patients. So, we know they have inflammatory arthritis, but they come in with Achilles tendinitis, how do we know if it's inflammatory or noninflammatory, because they've been running more? So, this is very challenging.
Ultrasound can be helpful; it doesn't always solve the problem. So, if we see that the inflammation is really at the site of the insertion or just right above the insertion, then that may be more inflammatory. And if we see that the inflammation is more in the body of the tendon, or you see tendinosis, and less actual inflammation, maybe micro tears, for example. Then that might suggest it’s more of a mechanical issue. But it's really difficult to say for sure, in most cases. Most of the time, it's not that clear.
So, there's a couple things to do. One is make sure that the rest of the disease is under control, and if there's other reasons to switch therapy, you might consider switching therapy. I refer a lot of these patients to sports medicine. So, we do this typical conservative treatment, for example, for Achilles tendonitis, and then kind of monitor if the rest of their disease is under control. But it can be really difficult. So physical therapy and physical therapists can be your help - your friend in this too, and get their input on what's going on as well.
Now, before we close, Dr Ogdie, are there any biomarkers for monitoring activity? And is there anything coming down the pipeline that you've been following, from this standpoint?
Yeah, this is kind of one of the holy grails of PsA that we really like is a biomarker that can help us follow the disease. And in reality, there are not any that are, you know, perfect biomarkers right now. The best we have is C-reactive protein, and CRP we know to only be elevated in about half of our patients. It’s really fascinating. You can see a patient with multiple joints that are swollen, and you can palpate that the fact that there's lots of synovitis and their CRP is basically normal, it's just mind boggling. But it's just the type of inflammation. CRP is largely driven by IL-6. And we know that many of our patients, for some reason, just don't have that elevated. So, it doesn't always track with therapy.
Now, sometimes I still check it because, you know, if someone has had one that was elevated, if they're kind of in the midst of developing a flare or they're in a flare, I check it and it's elevated, then in that person, it might be helpful to follow. For the person is always stone cold normal, it’s not helpful to follow.
Are there other biomarkers coming down the line? There's a lot of work going on to understand whether or not there's biomarkers that differentiate between osteoarthritis and PsA, or rheumatoid arthritis and PsA. At EULAUR and ACR the last couple years, there's been a few, abstracts that have been addressing this, so I think we're getting closer to that. But I think there's still a lot of work yet to do in defining new biomarkers for the disease.
Well, as that brings us to the end of our program, I want to thank my guest for helping us better understand how we assess disease activity in PsA. Dr Ogdie, it was great speaking with you today. Thank you.
Thanks so much.
This industry podcast was sponsored by Novartis US Clinical Development and Medical Affairs. If you missed any part of this discussion or to find others in this series, visit reachmd.com/living-rheum. This is ReachMD. Be part of the knowledge.