Estimates from the National Psoriasis Foundation indicate that more than 8 million people in the U.S. suffer from psoriasis and that approximately 30% of those individuals develop psoriatic arthritis (PsA).1 Given these statistics, roughly 2.4 million people in the country are likely affected by PsA. Moreover, patients with this systemic condition carry a higher-than-average burden of cardiometabolic comorbidities, such as diabetes, hypertension, cardiovascular disease—and obesity.
“Obesity is one of the stronger risk factors for development of psoriatic arthritis, along with severe psoriasis, history of joint trauma, family history and general inflammatory bowel disease,” says Alexis Ogdie, MD, MSCE, rheumatologist and associate professor of medicine and epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, and director of the Penn Psoriatic Arthritis and Spondyloarthritis Program.
The Weight Factor
Given the progressive nature of PsA, the earlier the disease can be diagnosed the better the long-term treatment outcome, says Dr. Ogdie. However, any diagnosis of PsA can take time, as undiagnosed patients generally first go to their primary care doctor, who might find inflammatory conditions that point to PsA. “Having uveitis or inflammatory bowel disease, for example, might elevate the likelihood that the patient’s joint complaints are psoriatic arthritis, and speed up diagnosis,” Dr. Ogdie notes.
However, an obese patient, particularly one without any of these telltale inflammatory conditions, can be especially difficult to diagnose, according to Dr. Ogdie. “People with obesity have a higher prevalence of osteoarthritis, so this can be hard to separate out—are these symptoms of osteoarthritis, is this mechanical in general, or is it psoriatic arthritis?” she says. “Patients with obesity have a higher prevalence of fibromyalgia and that’s also sometimes difficult to distinguish from PsA.”
Dr Ogdie
Weight also factors in when considering the patient’s potential responsiveness to drug therapy. M. Elaine Husni, MD, MPH, is a rheumatologist at the Cleveland Clinic’s Department of Rheumatic and Immunologic Diseases, and a researcher at its Lerner Research Institute. “If we focus on psoriatic arthritis patients, there are a lot of disease-modifying anti-rheumatic drugs [DMARDs] available,” she says. “In general, we know that certain medications don’t work as well when you have an elevated BMI, and that outcomes for surgery and other procedures are not as positive when patients are overweight or obese. For example, with anti-TNF [tumor necrosis factor] inhibitors, there is research showing that patients with an elevated BMI will take a longer time to reach minimal disease activity when compared to patients with a normal BMI. We also know that if a patient reduces their elevated BMI down to a normal one, that the drugs work better.”4,5
In addition to maximizing the effectiveness of medications, weight reduction can help patients with PsA in other ways. “All of your cardiometabolic comorbidities may escalate when you have obesity, and, because psoriatic arthritis has a higher burden to begin with, due in part to an ongoing low-grade inflammatory state, the higher BMI just adds to this issue,” explains Dr. Husni. “We consider weight to be a modifiable risk factor and that’s why we really want to help change this factor.”
Broaching the Subject
Once a diagnosis of PsA has been reached, the issue of obesity becomes more central to the conversation of what to do next. This can be a difficult and sometimes delicate aspect of the patient’s care. No one goes to a doctor to receive a lecture on weight loss. For people struggling with obesity, such conversations are often painful and anything but helpful because they have likely heard it all before. Both Dr. Ogdie and Dr. Husni emphasize the importance of fostering a safe, nonjudgmental relationship with these patients. For the first visit, that means providing as much objective information as possible before venturing into more sensitive areas.
After an initial assessment to identify the patient’s comorbidities and health history, a physical exam to understand what is happening with the joints, and a discussion of appropriate medications to address symptoms, Dr. Ogdie talks to obese patients about their cardiovascular risk based on their lipid profile.
Dr. Ogdie then proceeds to a discussion of body mechanics. “We can take care of joint inflammation, but that doesn’t address how well their body is moving,” she says, noting that her patients are usually referred to physical therapy for that. From there, she moves on to talking about depression or anxiety. Patients with psoriasis and psoriatic arthritis have an elevated risk of mood disorders, which increases the likelihood of unhealthy lifestyle habits.6
“Then at some point, depending on how the patient is responding, I bring up the weight,” says Dr. Ogdie. “If they are interested in hearing more, I might talk about how healthy diets, such as cutting out simple carbs, can help psoriatic arthritis. I might bring up the patient’s BMI and make it clinical, saying that we know that patients with a BMI of over 30 don’t respond as well to therapy and that if you reduce body weight by 5% to 10%, you’ll likely significantly improve your response to therapy.”
If obesity affects your patient, you need to look around & see what resources you can use to build a team to address it.
—M. Elaine Husni, MD, MPH
How far this conversation goes, however, is up to the patient. “The last thing you want is to overwhelm your patients on the first visit, when they are dealing with a diagnosis of a chronic illness,” stresses Dr. Husni. “Obviously, they’re there to hear about the illness itself and treatments for psoriatic arthritis. So instead of listing all the advice right off the bat, I like to choose which associated issue to discuss at a particular visit. If it is time to talk about weight management, I ask for permission to talk about their weight. Some patients say, ‘Yeah, bring it on, what do you know about obesity, what can I do?’ and others say, ‘You know, I’ve heard it all. I’m really trying, and I don’t want to talk about it right now.’ In that case, I’ll say, ‘Oh, that’s okay, we don’t have to address this at this visit.’
“If you simply list all the things someone needs to do while getting their arthritis treated with anti-TNF therapy—such as lose weight, exercise three times a week, raise their heart rate 20 minutes a day and eat a well-balanced diet—they’re just not going to do it.”
Physical activity can be harder for obese people, and those who also have PsA are especially wary about exercise because they fear it might hurt their joints and/or worsen their symptoms—unfounded yet common fears, according to Dr. Ogdie. These patients may need extra reassurance and guidance from their medical team to feel safe about exercising. It can also be helpful to remind patients that additional weight gain is more likely when they are not physically active.
Treatment Strategies
The standard treatment approach for all patients with PsA may not be as effective in a patient with a BMI above 30. Although studies show the obese body may not respond as well to medications typically used to address inflammation as non-obese bodies do, the reasons for this are still being explored.
“We do know that adipocytes produce inflammatory cytokines, which may increase the obese patient’s joint inflammation,” says Dr. Ogdie. “In addition, giving every patient with PsA the same 40 mg dose of adalimumab regardless of their weight really doesn’t make sense, but that’s what the original study suggests. It’s just one dose for everybody. So patients not getting the appropriate dose for their body weight may also play a role.”7
Additional challenges to treatment include “the typical lifestyle habits that go along with having a chronic disease,” says Dr. Husni. These may include poor sleep, inability to exercise and a worsened response to stress, all of which can be more pronounced when dealing with a chronic illness.
“Given the evidence now, we have shifted our attitude; improvements in our lifestyle behaviors are important and not likely something that is optional,” Dr. Husni says. “We encourage our patients to discuss how to modify their lifestyle behaviors when they have a chronic illness. These ‘wellness strategies’ may not be a luxury, but rather, a critical adjunctive concern that needs to be addressed. They are just as important as treating the disease.”
Stressing that lifestyle changes are intertwined with psychosocial health, she advocates for a whole-patient approach, which she feels is especially key for obese patients, whose condition is frequently misunderstood.
“It’s easy for us to dismiss people who are obese and think they don’t care about themselves or that they choose not to change their habits,” Dr. Husni says. “However, there are different stages of treating obesity now. We have a greater understanding of the hormones related to obesity, such as ghrelin and leptin, and how they can become dysregulated to result in a higher weight set point.”
Dr. Husni
At the Cleveland Clinic, Dr. Husni can refer patients with more urgent weight-related needs to the clinic’s Endocrine and Metabolic Institute for care. Dr. Ogdie reports that Penn is currently running a diet trial for patients with a BMI of 25–40. The focus, she explains, is on lifestyle changes over monitoring weight, although both are in the mix. She has referred her patients to the study.
Dietary guidance, although helpful, should be just part of a broader treatment plan for obese patients with PsA, say both rheumatologists. “It’s important that we understand all the different comorbidities of psoriatic arthritis, obesity being one of them. And if obesity affects your patient, you need to look around and see what resources you can use to build a team to address it,” says Dr. Husni.
In this regard, she acknowledges the benefit of practicing rheumatology in a co-management clinic. “Part of our job is to collect a patient’s profile of risk factors. Then we can build our team (bring in other specialists) to help address these factors,” she explains. “I have dermatologists, cardiologists and psychologists. I have a smoking cessation program. We see these patients over a lifetime, and we help them prioritize their health issues. So if obesity needs to be prioritized because they’re cycling through a lot of medications and not improving, they may consider getting to a more normal BMI. If a patient is in a low disease activity state with stable exams, labs and imaging, I may prioritize the psychosocial aspects for that patient rather than escalating DMARDs. It’s just not one size fits all.”
Therein lies another challenge. How many patients in the U.S. have access to a team of specialists to help resolve a complex and multifaceted problem like psoriatic arthritis with obesity? How many rheumatologists have the resources to gather a team, much less the time to oversee team-based care?
“I have the luxury of a full hour for a new patient visit and then 20 minutes or so for a return patient visit, which not everyone has,” acknowledges Dr. Ogdie. Still, it is not enough. Penn is starting a single-arm trial funded by a grant from the Rheumatology Research Foundation testing a new model that, she says, “basically takes it out of the doctor’s hands” by having a nurse or nurse practitioner handle regular visits. At Dr. Ogdie’s office, a nurse practitioner takes a full day of telemedicine calls for existing patient check-ins once a week. Education resources for the patient, such as handouts, also carry some of the load.
Finally, what does the current U.S. health system allow? “It would be great for people to understand the costs of obesity in psoriatic arthritis because insurance companies should really be thinking about covering those costs,” says Dr. Ogdie. “As it is, it’s hard to get people to physical therapy because of the high copay, and patients often can’t get coverage for a nutritionist unless they have cancer. They can’t get the mental healthcare they need because our current health system isn’t set up to help. Those are the kinds of things that need to change to help these patients.”
Linda Kossoff is a medical writer based in Los Angeles.
References
- National Psoriasis Foundation. Psoriasis Statistics. https://www.psoriasis.org/psoriasis-statistics.
- Centers for Disease Control and Prevention. Adult Obesity Facts. https://www.cdc.gov/obesity/data/adult.html.
- Kumthekar A, Ogdie A. Obesity and psoriatic arthritis: A narrative review. Rheumatol Ther. 2020 Sep;7(3):447–456.
- Klingberg E, Bilberg A, Bjorkman S, et al. Weight loss improves disease activity in patients with psoriatic arthritis and obesity: An interventional study. Arthritis Res Ther. 2019 Jan 11;21(1):17.
- Di Minno MN, Peluso R, Iervolino S, et al. Weight loss and achievement of minimal disease activity in patients with psoriatic arthritis starting treatment with tumour necrosis factor alpha blockers. Ann Rheum Dis. 2014 Jun;73(6):1157–1162.
- Mogard E, Bremander A, Haglund E. A combination of two or more unhealthy lifestyle factors is associated with impaired physical and mental health in patients with spondyloarthritis: A cross-sectional study. BMC Rheumatol. 2022 May 25;6(1):29.
- Mease PJ, Gladman DD, Ritchlin CT, et al. Adalimumab for the treatment of patients with moderately to severely active psoriatic arthritis: Results of a double-blind, randomized, placebo-controlled trial. Arthritis Rheum. 2005 Oct;52(10)3279–3289.
