Subsets in psoriatic arthritis formed by cluster analysis.

Area of Science:

• Rheumatology
• Dermatology
• Immunology

Background:

• Psoriatic arthritis (PsA) is a complex inflammatory condition with varied clinical manifestations.
• Understanding patient heterogeneity is crucial for targeted treatment strategies.

Purpose of the Study:

• To stratify psoriatic arthritis patients into distinct subgroups.
• To identify subgroups based on dermatological, clinical, laboratory, immunological, and radiological features.
• To improve the classification of psoriatic arthritis phenotypes.

Main Methods:

• Hierarchical cluster analysis (Ward's method) was applied to data from 100 psoriatic arthritis patients.
• Standardized data collection included dermatological, arthritis pattern, laboratory, immunological, and radiological findings.
• Patient subgroups were defined based on the clustering results.

Main Results:

• Seven distinct subgroups of psoriatic arthritis patients were identified.
• Subgroups included a 'polyarticular group' (mild psoriasis), two 'RA-like groups' (serological/axial differences), an 'oligoarticular group' (severe skin disease, female predominance), an 'erythrodermal group' (severe arthritis, erythroderma history), a 'distal form' group (sausage fingers, nail dystrophy), and a 'pustular group' (pustular psoriasis, nail dystrophy).
• Both arthritic status and skin disease type were significant in defining subgroups.

Conclusions:

• The identified subgroups highlight the diverse nature of psoriatic arthritis.
• Classification based on both skin and joint involvement offers a more comprehensive understanding of the disease.
• These subgroups may facilitate personalized treatment approaches for psoriatic arthritis patients.