Identification of clinical phenotypes of peripheral involvement in patients with spondyloarthritis, including psoriatic arthritis: a cluster analysis in the worldwide ASAS-PerSpA study

Abstract

ObjectiveTo identify clusters of peripheral involvement according to the specific location of peripheral manifestations (ie, arthritis, enthesitis and dactylitis) in patients with spondyloarthritis (SpA) including psoriatic arthritis (PsA), and to evaluate whether these clusters correspond with the clinical diagnosis of a rheumatologist.MethodsCross-sectional study with 24 participating countries. Consecutive patients diagnosed by their rheumatologist as PsA, axial SpA or peripheral SpA were enrolled. Four different cluster analyses were conducted: one using information on the specific location from all the peripheral manifestations, and a cluster analysis for each peripheral manifestation, separately. Multiple correspondence analyses and k-means clustering methods were used. Distribution of peripheral manifestations and clinical characteristics were compared across the different clusters.ResultsThe different cluster analyses performed in the 4465 patients clearly distinguished a predominantly axial phenotype (cluster 1) and a predominantly peripheral phenotype (cluster 2). In the predominantly axial phenotype, hip involvement and lower limb large joint arthritis, heel enthesitis and lack of dactylitis were more prevalent. In the predominantly peripheral phenotype, different subgroups were distinguished based on the type and location of peripheral involvement: a predominantly involvement of upper versus lower limbs joints, a predominantly axial enthesitis versus peripheral enthesitis, and predominantly finger versus toe involvement in dactylitis. A poor agreement between the clusters and the rheumatologist‘s diagnosis as well as with the classification criteria was found.ConclusionThese results suggest the presence of two main phenotypes (predominantly axial and predominantly peripheral) based on the presence and location of the peripheral manifestations.

Enthesitis indices identify different patients with this characteristic in axial and peripheral spondyloarthritis and also in psoriatic arthritis: ASAS-PerSpA data

“…The present study is an ancillary analysis of data from the international and cross-sectional ASAS-PerSpA study that included 24 participating countries [ 3 ]. Both the design and patient recruitment have been described elsewhere [ 3 ].…”

“…Patients had to be capable of understanding and completing questionnaires. The present study was developed according to the guidelines of Good Clinical Practice, described in the original study [ 3 ]. It was also approved by the ethics committees of each country, and written informed consent was obtained from all subjects.…”

“…Spondyloarthritis (SpA) represents a group of rheumatic inflammatory diseases characterized by the involvement of the spine and sacroiliac joints. These entities have been classified by the Assessment of Spondyloarthritis International Society (ASAS) [ 1 , 2 ] according to their clinical presentation as predominantly axial spondyloarthritis (axSpA) or predominantly peripheral spondyloarthritis (pSpA) [ 3 ]. Psoriatic arthritis (PsA) represents a particular subtype of SpA that is characterized by chronic inflammatory arthritis in patients with a personal or familial history of psoriasis [ 4 ].…”

Management of psoriatic arthritis: a consensus opinion by expert rheumatologists

“…Early diagnosis, comprehensive disease assessment, and proper treatment are the mainstays to guarantee the best outcome of PsA patients, both in the short and long-term. In the past two decades, relevant research progresses have been made in understanding pathophysiology and defining clinical phenotypes (6)(7)(8)(9)(10)(11), and therapies targeting new mechanisms of action have been developed (12). Despite these improvements, the management of PsA is still difficult and many unresolved questions in this field await an answer (13).…”