Assessment and treatment of Down syndrome-associated arthritis: a survey of pediatric rheumatologists.

Background: Inflammatory arthritis in children with Down syndrome (DS) was first described in 1984 and is now termed Down syndrome-associated arthritis (DA). Studies have shown that DA is under-recognized with a 19-month average delay in diagnosis. Additionally, most patients present with polyarticular, rheumatoid factor (RF) and anti-nuclear antibody (ANA) negative disease. Current therapies for juvenile idiopathic arthritis (JIA) have been used, but appear to be poorly tolerated, more toxic and less effective in patients with DA. There is currently no standardized approach to the assessment or management of DA. The objective of this study was to describe provider perspectives toward diagnostic and treatment approach of DA, to provide baseline information upon which to design future studies.
Methods: An electronic survey, organized into sections regarding individual practices of assessment and treatment approach of DA, was sent to the Pediatric Rheumatology electronic list-serv. Survey responses were voluntary and results were analyzed by descriptive statistics.
Results: Of 90 survey responses received, 89 were included in the analysis (one was a duplicate response). The respondents were mostly pediatric rheumatologist (94%), with greater than 10 years of experience (55%). The majority (64%) currently see 1-3 patients with DA. Most view DA as the same disease as JIA (73%), and the majority (63%) use a combination of history, exam and imaging to diagnose DA. The most ordered diagnostic tests are CBC (97%) and ESR (96%). The most used treatments include NSAIDs (94%) and methotrexate (91%) followed by anti-TNF agents (90%). Methotrexate is most administered by subcutaneous route (84%) at a dose of 15 mg/m ² (56%). Oral corticosteroids were only used in 19% of the patients with DA.
Conclusion: This is the first study to evaluate provider perspectives towards the diagnostic and treatment approach of DA. Most pediatric rheumatologists feel that DA and JIA are synonymous, and similar approaches to diagnosis are employed, utilizing history, physical exam, laboratory tests, and imaging modalities. DA is treated similarly to JIA with initiation of NSAIDs, disease-modifying anti-rheumatic drugs and biologic therapy. More research is needed to determine optimal screening and therapeutic approach specific to DA.