The study of a relatively large group of juvenile pediatric spondyloarthritis patients revealed there’s a need for more accurate classification criteria for disease identification.
The study also showed that a family history of spondyloarthritis is the main risk factor for persistent active disease.
Most cases of pediatric spondyloarthritis (SpA) fall under enthesitis-related arthritis (ERA) or psoriatic arthritis (PsA). ERA is a subcategory of juvenile idiopathic arthritis, which is a group of diseases that are classified according to the so-called 2002 Edmonton criteria.
According to this classification system, patients with juvenile SpA (JSpA) who do not fulfill either the ERA or PsA criteria fall under an undefined juvenile arthritis category.
Another classification method is the Assessment of Spondylarthritis International Society (ASAS).
Now, researchers aimed to assess initial presentation and outcomes of a relatively large group of JSpA patients, as well as the accuracy of currently used classification criteria.
The study “Clinical features of children with enthesitis-related juvenile idiopathic arthritis / juvenile spondyloarthritis followed in a French tertiary care pediatric rheumatology centre,” was published in the journal Pediatric Rheumatology,
It involved patients evaluated as having ERA or JSpA at a French national reference center for juvenile arthritis between 2008 and 2015. A total of 114 patients were included with a mean follow-up of 2.6 years.
Data regarding several criteria were collected, including age at first visit, inflammatory and autoimmune disease, and psoriasis history, clinical course, and response to treatment.
Researchers found that according to the Edmonton classification criteria, 46% (53 patients) and 1.75% (two patients) of those in the study had been diagnosed with ERA and PsA, respectively, while according to the 2011 ASAS criteria, 73% (83 patients) could be classified as having peripheral SpA.
During follow-up, most patients (87%) developed peripheral arthritis (mainly in the lower limbs).
Although axial disease and sacroiliitis — an inflammation of one or both of the sacroiliac joints at the place where the lower spine and pelvis connect — were rare at disease onset, axial disease was observed in 63% of patients at the latest follow-up, and sacroiliitis in 47% of the cases.
A familial history of SpA was the only prognostic factor associated with active disease and sacroiliitis.
“We confirm that JSpA is characterized by its peripheral pattern at disease onset, with peripheral arthritis and enthesitis. However, axial disease developed over the next five years in more than half our patients,” the researchers wrote.
They added that a “familial history of SpA is one of the major prognostic factors associated with both sacroiliitis and persistence of active disease over years, favoring the close follow-up of such patients to initiate effective and timely treatment.”
The team also suggested that the current “revised Edmonton criteria were less sensitive than ASAS criteria to classify patients as having childhood-onset spondyloarthropathies … which merits, among other considerations, the ongoing effort to improve classification criteria of [juvenile idiopathic arthritis].”