Diagnosis

New Goals of Therapy for PsA, RA Help Differentiate the Conditions

The relationship between psoriasis and arthritis is unique. There are various ways to determine if a patient with psoriasis has inflammatory arthritis; arthritis can occur concurrently, and inflammatory joint symptoms can arise prior to any skin changes.

 

Jon Giles, MD, MPH, who is an associate professor of medicine at Columbia University College of Physicians and Surgeons, highlighted differences in diagnosis and management of psoriatic arthritis (PsA) and rheumatoid arthritis (RA).  

 

PsA is a heterogenous disorder, which can lead to challenges in diagnosis and management. Predictors of PsA include psoriasis at the scalp and intergluteal regions, as well as nail pitting and a family history of PsA.

 

Due to its heterogeneity, there are various ways to measure PsA. Some tools include PsARC, ACR joint count, and BASDAI. Giles said it can be very difficult to assess how active PsA is in a patient.

 

RA has genetic susceptibility, different from PsA. However, not all patients who have genetic susceptibility will develop RA. In addition, smoking has strong interaction with genetic susceptibility of the disease, which can lead to activation of immune cells that induces the release of cytokines.

 

RA classification is easier than PsA since it is typically based on swollen joints. Since there are not any antibodies helpful for identifying PsA, diagnosis can be more challenging, according to Giles. Treatment options for PsA are also changing.

 

“This is an evolving area,” he said. “[However], I want to express that traditional, nonbiologics still have an important role in the treatment of PsA.”

 

 

Target to treatment >>

For the first time, there are therapeutics unique to PsA, not for both PsA and RA. Giles reviewed the recent ACR guideline on active PsA. He said the guidelines were developed by answering questions to a scenario. Another treatment approach is to use the GRAPPA Treatment Schema for Active PsA, where treatment strategies are decided on PsA features.

 

“ACR guidelines don’t discuss this so following the GRAPPA treatment schema is easier,” Giles said. “I like this approach and its more [like] the way I and other rheumatologists treat; we base treatment on predominant phenotype.”

 

Giles said there still is a role for traditional DMARDS. They are less expensive and prevent antibody generation compared to other biologics. However, they are not disease modifying and have suboptimal dosing. Different therapeutic options “beg” specialists to constantly reevaluate patients and change therapy if they aren’t responding, Giles said.

 

Something to keep in mind is that newer therapies for PsA can be effective for a year or two then sometimes stop working, so “having other agents to use is very helpful, particularly ones that have different mechanisms of action, since the disease is so heterogenous,” said Giles.

 

For RA, the primary target for treatment is clinical remission. Low disease activity could also be a treatment goal among patients with long-standing disease. There are various disease modifying pharmacotherapies for the treatment of RA.

 

“There is much more evidence for oral nonbiologics like MTX to have disease modifying effects on the joints, as opposed to PsA,” Giles said, adding that MTX should be first line therapy for early RA.

 

For moderate to severe disease, the 2015 ACR RA treatment guidelines recommend a combination of a traditional DMARD (MTX) with TNFi or non-TNF biologic, according to Giles’ presentation.

 

PsA has extra-articular manifestations similar to RA. These include osteoporosis and fatty liver disease. However, there are various manifestations unique to PsA such as nail disease, axial involvement, and enthesitis. Manifestations can lead to comorbidities like increased risk for infection, depression, and fatigue.

 

“Comorbidities impact treatment decisions, quality of life, and mortality in both RA and PsA,” Giles said. “Recognizing and monitoring comorbidities is a major aspect of RA and PsA management,” adding that early and aggressive treatment may reduce comorbidities.

 

Giles said building a one-on-one relationship with the patient is crucial for long-term management. He recommended the following to improve communication in practice:

 

  • maintain patient motivation and engagement in care;
  • set realistic expectations;
  • take a health-literate approach to prescribing and educating patients; and
  • understanding/exploring reasons for decline in adherence.

 

Reference:

Giles J. New goals of therapy for psoriatic and rheumatoid arthritis: Managing comorbidities, preserving joints, and pursuing remission with biologics. Presented at: Interdisciplinary Autoimmune Summit; April 5-7, 2019; Chicago, IL.