Poor prognosis in juvenile-onset ankylosing spondylitis was associated with earlier onset of symptoms and the presence of psoriasis, according to data presented at the 20th European Pediatric Rheumatology Congress held in Ljubljana, Slovenia.
Although the researchers did not find delayed diagnosis of juvenile-onset ankylosing spondylitis (JoAS) correlative with poor outcome, Dr. Deepak Jadon of the Royal National Hospital for Rheumatic Diseases in Bath, England, said, "A better understanding of clinical phenotype, disease history, and prognosis provides insights into pathogenesis, potential targets for therapy, and allows for patients with worse prognosis to receive intensive therapy earlier in their disease course."
Dr. Deepak Jadon
To evaluate which clinical factors were implicated in poor prognosis of AS, Dr. Jadon and his colleagues prospectively compared the clinical, functional, and genetic outcomes of 143 JoAS patients with those of 413 adult-onset AS (AAS). JoAS is defined as AS occurring at or before age 16 years. All study participants had been diagnosed by a rheumatologist using the modified 1987 New York criteria and were patients of a secondary rheumatology hospital in the United Kingdom.
The investigators compared the sex, age of symptom onset (only in the JoAS group), and the age when the diagnosis was made. They also measured each patient’s most recent Bath Ankylosing Spondylitis Functional Index (BASFI), Bath Ankylosing Spondylitis Activity Index (BASDI), Bath Ankylosing Spondylitis Metrology (BASMI) scores; and their HLA-B27 genotype status. All patient histories were assessed for the occurrence of psoriasis, uveitis, enthesitis, inflammatory bowel disease (IBD), and AS-related orthopedic surgeries.
At the time of assessment, JoAS cases were a mean 2.9 years younger than were AAS cases (49.0 vs. 51.9 years). There was a mean difference in disease duration of 6.7 years between the groups (JoAS, 26.0 years, vs. AAS, 19.3 years).
Using logistic regression to adjust for the differing time since diagnosis, Dr. Jadon and his colleagues found that JoAS cases were significantly more likely than AAS to have had AS-related surgery (18.9% vs. 8.0%). JoAS cases were also more likely to have concurrent IBD (11.2% vs. 6.8%), although the difference was not statistically significant. Poor BASFI scores of 5 or greater occurred in significantly more JoAS cases with psoriasis than in AAS cases with psoriasis (55% vs. 25%, respectively). AS-related surgery had occurred in significantly more of the JoAS cases with psoriasis than in those without it (43% vs. 15%, respectively).
The researchers did not find statistical differences between the JoAS and AAS groups with respect to sex, HLA-B27 positive status, psoriasis, enthesitis, or uveitis (all cases or HLA-B27–positive cases). BASFI, BASDAI, and BASMI were also all statistically insignificant, although there was a trend for JoAS cases with a poorer BASFI to have had earlier symptom onset than did those with a BASFI score greater than 5 (mean age 12.5 vs. 13.4 years). There also was a trend for JoAS cases with AS-related surgery to have had a younger age of symptom onset than did those without surgery (mean age 12.5 vs. 13.3 years).
The data "provide an opportunity to apply stratified medicine and improve the patient’s health care experience," Dr. Jadon said.
He and his colleagues reported no relevant disclosures.