Subsets in Psoriatic Arthritis formed by Cluster Analysis

Abstract

The aim of the study was to create subgroups among psoriatic arthritis patients on the basis of dermatological features, clinical pattern of arthritis, and laboratory, immunological and radiological findings. Data on 100 patients were expressed in a standardised form and entered into hierarchical cluster analysis according to Ward's method. Seven subgroups were created. Fifty-six patients with mild psoriasis were sorted into a 'polyarticular group'. Two 'RA-like groups' were formed, differing from each other serologically and in axial involvement. In an 'oligoarticular group' (18 patients) serious skin disease and female gender predominancy were found to be characteristic. Eight patients with polyarticular arthritis were assigned to an 'erythrodermal group', in which polyarticular arthritis, mutilating, severe arthritis and a history of erythroderma were characteristic. Close to this group on the dendrogram eight women were sorted into a 'distal form'. Sausage fingers were frequent, and nail dystrophy was present in every case. In a 'pustular group' (three patients) the different type of skin involvement was considered and nail dystrophy was common. In the newly created subgroups not only the arthritic status, but also the type of the skin disease, played a determining role.

Psoriasis: characterization of six different clinical phenotypes

“…Factor analysis and clustering methods were applied to discover the relationship between clinical variables measured in the study sample. Related statistical methods have frequently been successfully applied in other fields of medicine (9)(10)(11)(12)(13)(14)(15)(16)(17), and very recently in dermatology (18)(19)(20)(21). Using such a methodology, we were able to identify six statistically different groups of patients characterized by specific association of clinical characterictics.…”

Gender difference in disease expression, radiographic damage and disability among patients with psoriatic arthritis

“…Ankylosing spondylitis (AS), the prototype of the SpA with a predominant spinal involvement, is a male predominant disease,1 while psoriatic arthritis (PsA) is generally considered a disease that affects men and women equally 2–6. However, a few studies suggested that PsA is more prevalent in male subjects7–9 while others have shown a female predominance 10 11…”

Topographic Patterns of Cartilage Lesions in Knee Osteoarthritis

“…For example, finger arthritis has been classified based on the finger(s) affected, gender, and biomarkers. 26 Analogously, knee OA could be classified based on the size of the cartilage lesions in the compartments of the joint. Once samples are classified into groups, mean lesion topographies can be determined for each group to identify characteristic patterns.…”