Editorial theme | Points to consider in the development of PsA in individuals with psoriasis from the EULAR task force

In approximately 70% of individuals with psoriatic arthritis (PsA), psoriasis occurs first and can precede PsA development by decades.¹ Skin involvement in psoriasis could be predictive of increased risk of PsA occurrence.¹ Identifying predictors for PsA development could allow for earlier treatment, or prevention of PsA in these individuals.¹

It has been suggested that there are three stages between psoriasis and PsA development, as shown in Figure 1.² Building on this, the European Alliance of Associations for Rheumatology (EULAR) developed a task force to produce guidance for clinical trials focused on the prevention of PsA, and the management of individuals at risk of PsA.¹ Here, we discuss the main guidance provided from the task force.

Figure 1. Stages from psoriasis to early PsA*

PsA, psoriatic arthritis.
*Data from Scher, et al.²

Findings¹

The EULAR task force comprised 29 members: 21 rheumatologists, five dermatologists, two patient partners, and one healthcare professional.

The task force had three objectives:

• Defining the main features present in individuals who transition from psoriasis to PsA
• Characterizing the phenotype of new-onset PsA
• Identifying the stages of progression from psoriasis to PsA, relevant to PsA prevention

The method of developing these recommendations followed EULAR standardized operating procedures, using a consensual approach and systemic literature research. The task force developed five overarching principles, as shown in Figure 2.

Figure 2. Overarching principles* 

LoA, level of agreement; PsA, psoriatic arthritis.
*Adapted from Zabotti.¹

The task force also identified points to consider for clinical trials on the prevention or interception of PsA and on the management of psoriasis in individuals at risk of PsA. These points were rated on the level of evidence (LoE) and level of agreement (LoA) for each point. Figure 3 illustrates the points to consider with the highest LoE (Level 5). Additional points to consider included:

• In clinical trials on prevention and interception of PsA:
  • Imaging in individuals with psoriasis could be used to identify those at risk of PsA (LoE, 3b; LoA, 9.1).
• For the management of psoriasis in individuals at risk of PsA,

• • arthralgia in individuals with psoriasis should be considered as a short-term predictor of PsA development (LoE, 3a; LoA, 9.2);
  • in individuals with psoriasis, joint and entheseal pain and functional limitation should be enquired about regularly and referral to a rheumatologist should be considered if present (LoE, 3b; LoA, 9.3);
  • imaging abnormalities in the absence of musculoskeletal symptoms should be considered carefully to ensure appropriate treatment (LoE, 3b; LoA, 9.5); and
  • individuals with psoriasis and obesity, nail disease, and/or extensive psoriasis should be considered at higher risk of PsA development long term (LoE, 3a; LoA, 9.3).

Figure 3. Points to consider with high LoE* 

LoA, level of agreement; LoE, level of evidence; PsA, psoriatic arthritis.
*Adapted from Zabotti.¹ 

Finally, the task force developed definitions for the phases of PsA development in individuals with psoriasis; this is shown in Figure 4.

Figure 4. Definitions of the phases of PsA development for use in clinical trials*

PsA, psoriatic arthritis.
*Data from Zabotti.¹

Conclusion

The recommendations of the EULAR task force provide an evidence-based framework for use in clinical trials on the risk of PsA development and for the management of individuals with psoriasis who may be at risk of PsA.¹ However, Zabotti highlighted that in patients with psoriasis without evidence of muscloskeletal involvement, imaging techniques such as ultrasound and magnetic resonance imaging should only be used in the clinical trial setting; there is currently no evidence that imaging can be used for risk stratification in PsA.¹ Therefore, it is important to differentiate between  points to consider for clinical trials and points to consider for the management of individuals with psoriasis at risk of PsA.¹