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Published on: March 1, 2024
Psoriatic arthritis spectrum in children: a multicentre observational study
Serena Pastore1, Alberto Tommasini2, Giorgia Martini3
1Institute for Maternal and Child Health, IRCCS Burlo Garofolo, Trieste, Italy.
Insights
Juvenile idiopathic arthritis (JIA) exhibits significant heterogeneity. Identifying distinct clinical clusters and incorporating psoriatic arthritis criteria improves diagnosis and classification of this complex pediatric condition.
Area of Science:
- Pediatric Rheumatology
- Immunology
- Genetics
Background:
- Juvenile idiopathic arthritis (JIA) is a heterogeneous autoimmune condition in children.
- Current classification criteria, such as the International League of Associations for Rheumatology (ILAR) criteria, may not fully capture the spectrum of JIA.
- Identifying distinct subtypes is crucial for targeted treatment and understanding disease progression.
Purpose of the Study:
- To describe the characteristics of children diagnosed with ILAR-defined JIA.
- To explore more sensitive and specific criteria for defining JIA, particularly focusing on psoriatic features.
- To identify clinical clusters within the JIA population.
Main Methods:
- A retrospective, observational, multicenter study included 73 patients diagnosed with JIA according to ILAR criteria.
- Unsupervised principal component analysis was used to identify clinical clusters based on ILAR and CASPAR criteria.
- Patients meeting ERA criteria with psoriatic features were classified as undifferentiated arthritis.
Main Results:
- Three distinct clinical clusters of JIA were identified, differing in age, psoriasis, dactylitis, and family history of psoriatic arthritis.
- Cluster 2 showed a significant association with family history of psoriatic arthritis and increased MTX treatment and tenosynovitis.
- Combining ILAR, CASPAR, and Vancouver criteria resulted in only two undifferentiated patients, suggesting improved diagnostic accuracy.
Conclusions:
- JIA presents with significant heterogeneity, necessitating criteria beyond ILAR for accurate classification.
- Incorporating family history of psoriatic arthritis and utilizing combined criteria (ILAR, CASPAR, Vancouver) enhances the diagnosis of pediatric psoriatic spectrum arthritis.
- Larger cohorts and comprehensive clinical data are needed for better categorization and treatment strategies for complex JIA cases.
Objectives:
The aim of this study is to describe characteristics of children with the International League of Associations for Rheumatology (ILAR)-defined juvenile idiopathic arthritis (JPsA) and to assess whether more sensitive and specific criteria for defining JPsA can be identified.
Methods:
A retrospective observational multicentre study was conducted including patients with a diagnosis of JPsA according to ILAR criteria. In this population, we identified clusters using as variables the clinical criteria of JPsA according to ILAR and the CASPAR clinical criteria. In addition, we defined as undifferentiated arthritis patients that met the ERA criteria, as defined by ILAR, and presented psoriatic features such as psoriasis or a history of psoriasis or psoriatic arthritis in a first-degree relative.
Results:
73 patients were enrolled. Three clinical clusters were found using unsupervised principal component analysis for the patients. Cluster 1 differed significantly for older patients and psoriasis. In contrast, Cluster 2 was mainly characterised by dactylitis and Cluster 3 was defined by family history of psoriasis and a significant prevalence of dactylitis. We also showed a statistically significant presence of familiarity for psoriatic arthritis in Cluster 2. The significance for all parameters evaluated did not change even when we included the patients with undifferentiated arthritis, except for MTX treatment, which was significantly more common in Cluster 2 (p=0.02), and tenosynovitis, also in Cluster 2 (p=0.05). Moreover, we evaluated our cohort by the Vancouver criteria. Combining the ILAR, CASPAR, and Vancouver criteria only two patients remain undifferentiated.
Conclusions:
Our study showed three clinical clusters with diverse demographic and clinical characteristics, indicating JPsA heterogeneity. The findings highlight the need to look beyond ILAR criteria for clinical variables, including family history of psoriatic arthritis. The ILAR, CASPAR, and Vancouver criteria improve the diagnosis of paediatric psoriatic spectrum arthritis. This complex disease population needs larger cohorts and clinical data, especially on axial involvement, to better categorisation and treatment.
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