Psoriatic Spondylitis: A Disease Manifestation in Debate: Evidences to Know for the Clinical Rheumatologist

Axial Disease in Psoriatic Arthritis: A Challenging Domain in Clinical Practice

Psoriatic arthritis (PsA) is a chronic inflammatory condition affecting about one-third of individuals with psoriasis. Defining axial involvement in PsA (axPsA) remains debated. While rheumatologists guide clinical practice, consensus on axPsA is still lacking. This paper explores historical and upcoming definitions from the Axial Involvement in Psoriatic Arthritis (AXIS) study, which aims to establish a validated axPsA definition. Epidemiological data reveal diverse axPsA prevalence rates, emphasizing its complex relationship with peripheral arthritis and enthesitis. Unique genetic, clinical, and radiological features differentiate axPsA from ankylosing spondylitis (AS), necessitating refined classification criteria. The recommendations from the Assessment of Spondylarthritis international Society (ASAS) provide valuable guidance due to the limited direct evidence. Emerging therapies, including interleukin-23 (IL-23) inhibitors or Janus kinase (JAK) inhibitors, are under investigation for axPsA. Currently, secukinumab, an interleukin-17 (IL-17) inhibitor, is an evidence-based option for axPsA management. However, given the variability in individual patient responses and disease manifestations, personalized, evidence-based treatment approaches remain essential for optimizing patient outcomes. In the final section, two real-life cases illustrate the challenges in managing axPsA, emphasizing the importance of tailored therapies. Achieving precision in defining axPsA remains a formidable task, making detailed criteria essential for effective strategies and improving patient outcomes.

Validity and reliability of the Duruöz Hand Index in patients with psoriatic arthritis

OBJECTIVE

The Duruöz Hand Index (DHI) is a valuable scale developed for evaluating hand functions of patients with rheumatoid arthritis and subsequently proven to be valid and reliable in various diseases. This study aims to investigate the validity and reliability of the DHI in patients with psoriatic arthritis (PsA).

METHODS

Patients diagnosed with PsA according to CASPAR criteria were enrolled. The demographic, clinical, and functional characteristics of patients were evaluated. Functional assessment was performed with DHI, Hand Functional Index, Health Assessment Questionnaire, and VAS-disability scale. C-reactive protein level, patients' and physicians' global VAS, swelling and tenderness of the hand joints, gross grip strength and thumb strength, and disease activity assessments were recorded as non-functional parameters related to active disease status. Reliability was assessed by internal consistency (with Cronbach's-a) and test-retest intraclass correlation coefficient. Face, content, convergent, and divergent validities were applied.

RESULTS

One hundred and forty-four patients (74.3% female) were included in this study. The Cronbach's alpha coefficient was 0.963, and for the test-retest reliability of the DHI, the intraclass correlation coefficient was 0.904 (p < 0.001). DHI showed good correlations with the functional disability scales (Hand Functional Index, Health Assessment Questionnaire, VAS-disability), indicating its convergent validity and moderate to non-significant correlations with the non-functional parameters supporting its divergent validity.

CONCLUSIONS

Despite the occurrence of significant deformities and functional loss in PsA patients, there is a noticeable absence of specific tools tailored for PsA. Considering the intricacies associated with skin, nail, tendon, entheseal involvement, and arthritis, there is a need for straightforward tools in both clinical practice and studies involving patients with PsA. The DHI is a valid and reliable scale to evaluate the functional disability of hands in patients with PsA.

Disease characteristics, pathogenesis, and treatment controversies of axial psoriatic arthritis

Axial psoriatic arthritis (axPsA) has considerable overlap with axial spondyloarthritis (axSpA) but has some unique features that sometimes preclude classification into axSpA. It has some clinical and radiographic differences compared to axSpA. Imaging typically shows asymmetric syndesmophytes, mainly in the cervical spine, with less frequent sacroiliitis. It more commonly presents later in life and is associated with less severe inflammatory back pain than axSpA. The interleukin (IL) IL-23/IL-17 axis is central to the pathogenesis of both diseases. However, the response to therapies targeting these cytokines has been different. IL-23 inhibitors are ineffective in axSpA but may be effective in psoriatic arthritis (PsA). Recent post hoc analyses of clinical trial data with IL-23 inhibitors in PsA have raised the possibility of their efficacy in axPsA and need evaluation in future clinical trials. Moreover, there is a need for classification criteria for axPsA and better tools to assess therapeutic response.

MRI Findings in Axial Psoriatic Spondylarthritis

Psoriatic arthritis is a significant medical condition with a high prevalence, a wide variety of non-specific symptoms, and a high degree of overlap with other spondylarthritis disorders, particularly ankylosing spondylitis. Hence, knowledge of the magnetic resonance imaging (MRI) manifestations and a multidisciplinary strategy are required for the better management of these patients. We searched publications from the last 10 years and focused on the most relevant ones which discussed the classification criteria, the MRI characteristics of axial psoriatic arthritis, the importance of MRI for follow up, and the reliability of skin and synovial biopsy. Axial spondylarthritis can be diagnosed and followed up on using the well-established MRI technique and, additionally, a biopsy. The analysis and concordance between them can provide new directions for future studies.