Axial involvement develops within 5 years of juvenile spondyloarthritis diagnosis
Although children diagnosed with juvenile spondyloarthritis demonstrate a low rate of symptomatic activity at onset, there is a marked increase in axial involvement in most patients after 5 years, according to findings published in Pediatric Rheumatology.
“[Spondyloarthritis (SpA)] is defined by a high risk of axial disease, typically with sacroiliitis,” Maxime Goirand, MD, of Necker-Enfants Malades Hospital and Paris Descartes University, and colleagues wrote. “The pediatric form differs from that of adults by a more peripheral pattern of arthritis with less frequent axial disease, at least at disease onset. … Little is known about the long-term outcome of [juvenile] SpA.”
To analyze the early presentation and later outcomes of patients with juvenile SpA, as well as the risk factors for axial disease and disease activity, the researchers conducted a retrospective study of individuals evaluated for childhood-onset spondyloarthropathies at Necker-Enfants Malades Hospital and Saint-Vincent-de-Paul Hospital. The study included 114 patients with juvenile SpA or enthesitis-related arthritis who experienced disease onset while younger than 16 years. All participants were followed for a median of 2.5 years between January 2008 and December 2015.
Goirand and colleagues collected data on each participant regarding gender, age at disease onset, age at first visit, personal and familial history of inflammatory and autoimmune disease and psoriasis, presence of the HLA-B27 allele, description of the clinical course, date of first axial involvement, and biological and radiological tests from the medical chart. They also analyzed the proportion of patients diagnosed with enthesitis-related arthritis or SpA according to the revised Edmonton classification criteria, as well as the latest Assessment of Spondylarthritis International Society (ASAS) criteria.
According to the researchers, although axial disease was rare at disease onset, it appeared in 63% of patients after a median of 2.6 years (95% CI, 2.2-4.4). Sacroiliitis, which was also rare at onset, developed in 47% of patients after 5.3 years (95% CI, 4.1-7.7). Familial history of spondyloarthritis was associated with the presence of sacroiliitis (OR = 3.61; 95% CI, 1.5–8.7; P < .01) and active disease (OR = 2.98; 95% CI, 1.2–7.3; P = .02) at the latest follow-up. In addition, 69% of patients met the Edmonton criteria for enthesitis-related arthritis, while 92% fulfilled the ASAS criteria for peripheral spondyolarthritis (P < .001).
“We confirm that [juvenile] SpA is characterized by its peripheral pattern at disease onset, with peripheral arthritis and enthesitis,” Goirand and colleagues wrote. “However, axial disease developed over the next 5 years in more than half our patients. MRI is clearly a valuable tool to assess axial involvement, but its interpretation may be more difficult in children and require, in many cases, an experienced radiologist.”
The researchers also added that their findings suggest that the current revised Edmonton criteria for JIA were less sensitive than the ASAS criteria for classifying patients with childhood-onset spondyloarthropathies.
“The current revised Edmonton classification criteria lacked both specificity and sensitivity to classify [juvenile] SpA/ERA, which merits, among other considerations, the ongoing effort to improve classification criteria of [juvenile idiopathic arthritis],” Goirand and colleagues wrote. “Applying the 2011 ASAS criteria for peripheral SpA may be worth considering for [juvenile] SpA, as they showed high sensitivity to diagnose our patients both at their first assessment and at the last follow-up.” – by Jason Laday
Disclosure: Goirand reports an invitation to an international congress from Novartis. Please see the study for all other authors’ relevant financial disclosures.