New Research Into Psoriatic Arthritis
Psoriatic arthritis (PsA) is an autoimmune disorder that often presents serious clinical challenges to practitioners. The disease’s array of disabling manifestations and painful, chronic symptoms can be intermixed with comorbid health problems. Oftentimes, late diagnosis is a pressing danger, as it ratchets up the risk of permanent joint damage, severely compromising a patient’s long-term outlook.
“Part of the underdiagnosis of PsA is simply lack of knowledge and awareness among clinicians and patients that patients with psoriasis can have an immunologically-mediate arthritis condition associated with it,” noted Philip J. Mease, MD, Director of Rheumatology Research, Swedish Medical Center, and Clinical Professor at the University of Washington School of Medicine, Seattle, Washington.
The Warning Signs of PsA
Are Plaque Psoriasis Patients Under-evaluated?
Psoriasis occurs in 3.2% of the US population, according to current findings from the National Health and Nutrition Examination Survey.1 Of patients with psoriasis, 10% to 30% have PsA.
While this may implicate an intrinsic, pathogenic link between the 2 conditions, there is still a lack of understanding how the inflammatory T cell responses that sustain lesional skin inflammation are connected to the joint inflammation that characterizes PsA.2
Data from Corrona (Consortium of Rheumatology Investigators of North America) on the relationship between skin and joint disease was presented at the American College of Rheumatology (ACR) annual meeting, held in San Francisco, California. Researchers reported that patients in the PsA registry who had a higher percentage of skin involvement (>3% body surface area [BSA]) had worse outcomes.
Indeed, patients with >3% affected BSA were more likely to be disabled and less likely to achieve minimal disease activity (MDA), compared to patients with ≤3% BSA at enrollment. Patients with >3% affected BSA also showed slightly higher rates of comorbid health problems, including cardiovascular disease (61.25% vs. 59.4%), cancer (9.1% vs. 6.6%), and serious infections (5.1% vs. 4.4%), compared to those with ≤3% BSA, respectively.3
Even when the definition of MDA was modified, excluding BSA, the criteria still pointed to worse outcomes for patients with >3% BSA. It also should be noted that 3% BSA is a relatively low cutoff point. And yet “the extent of psoriasis lesions confers a significantly greater burden of disease in PsA,” reported Dr. Mease, a co-author of the study, which underscores the importance of effectively managing psoriasis symptoms in patients that also suffer from PsA.3
Treating Psoriasis, While Looking Out for PsA
Use of over-the-counter (OTC) and topical treatments for psoriasis management typically is considered the first line of defense. Consistent doses of ultraviolet B (UVB) phototherapy also can improve symptoms. Doctors even are using combination approaches, pairing topical therapies with biologic agents, like disease-modifying antirheumatic drugs (DMARD’s), tumor necrosis factor inhibitors (TNFi), or interleukin inhibitors, which have been shown to be effective and safe despite the risk of adverse events associated with chronic use.4
However, while practitioners continue to pinpoint the best treatment approaches to managing psoriasis lesions, clinicians still need to be on the watch for PsA incidence, which appears to be a source of dysfunction in overall patient management. The relatively recent PREPARE trial found that 41% of psoriasis patients diagnosed with psoriatic arthritis were not previously aware that they had PsA.5 New research presented at this year’s ACR meeting further corroborate these claims.
In an analysis of 1,002 patients with psoriasis, a meager 4.3% received joint exams.6 In addition, out of those with physician-reported or patient-reported joint pain, 79.0% and 90.7% did not receive joint exams, respectively. Patients that had physician-reported joint pain but no joint examinations reported much poorer utility scores, greater activity impairment, and more severe psoriasis.
Underdiagnosis of PsA is a concerning trend, given that commonly overlooked non-specific musculoskeletal symptoms, including joint pain, fatigue, and stiffness, are typical warning signs of the preclinical PsA phase.7 Interestingly though, physicians and patients alike seem to be more interested in pain and functional activity than skin disease associated with PsA.
BioTRAC is another ongoing, prospective registry for culling data on autoimmune disease management, specifically for patients being treated with infliximab (Remicade) or golimumab (Simponi). A group of 92 patients (52.2% male; mean age 48.7; disease duration 6.8 yr) were assessed at baseline. A majority of patients (84.8%) had received past treatments of a DMARD (methotrexate; 71.7%). Patients and doctors both showed a stronger inclination towards more concern over reported pain and HAQ-DI when evaluating the global status of PsA.8,9 This could be a hopeful sign that skin symptoms are not seen as inconsequential in PsA management.
Timely Treatment Decisions
Treatment decisions need to be timely, precise—perhaps even pragmatic—to improve outcomes and inhibit the disease’s radiographic progression. However, this may be a more perplexing task than it was in the past. For decades, methotrexate (Trexall, Rasuvo, others) was the proverbial drug-of-choice for PsA, but in the last few years, the practice has seen a ballooning inventory of pharmaceutical options.
“It’s unbelievable the amount of new treatments that are available for psoriatic arthritis today,” said Elaine Husni, MD, MPH, of the Cleveland Clinic Foundation in Ohio. The litany of TNFi, phosphodiesterase-4 inhibitors (PDE4i), and emerging investigational interleukin inhibitors present a bevy of therapeutic approaches to assess.
Figuring out the most effective, responsive treatment strategies is an area of burgeoning research. “It becomes a great area of research to figure out which person should get which medication for their psoriatic arthritis,” Dr. Husni told Practical Pain Management, and fortunately for practitioners, a major update of consensus guidelines is on the way, courtesy of GRAPPA, the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis.
At the ACR meeting, the non-profit GRAPPA published an abstract of their new 2015 treatment recommendations for PsA.10 The last time the organization updated their guidelines was back in 2009,11 and given the influx of new research and approved therapies for PsA, the 2015 update could serve as a useful guidepost (Figure 1, Table 1).