Abstract
Objectives: We aim to evaluate the proportion and characteristics of enthesitis-related arthritis (ERA) patients in whom medications can be withdrawn in daily practice and to analyze the factors associated with flare-ups during medication tapering of these patients.Methods: We retrospectively reviewed records of patients under 16 years old diagnosed with ERA from April 2001 to March 2020 in one tertiary medical center in Taiwan. Patients were categorized by different medication uses: conventional disease modifying anti-rheumatic drugs (cDMARDs) only and cDMARDs plus biologics. Demographics, laboratory data, presence of uveitis, and medication withdrawal rate were analyzed. Subgroup analysis was performed in the patients with cDMARDs plus biologics to identify factors associated with flare-ups during medication tapering of these patients. Statistical analysis was performed using R (v3.6.0).Results: There were 75 juvenile ERA patients with a median onset age of 10.28 years old. Nineteen (25.3%) patients used cDMARDs for disease control; 56 (74.7%) patients depended on cDMARDs plus biologics. Poly-articular involvement was noted in 29 (38.7%) patients, and it occurred more frequently in the cDMARDs plus biologics subgroup (cDMARDs only, 5.3%; cDMARDs plus biologics, 53.6%; P = 0.0001). ANA positivity was observed in 18 (24.0%) patients, and it occurred more frequently in the cDMARDs plus biologics subgroup (cDMARDs, 0%; cDMARDs plus biologics, 32.1%; P = 0.0038). The overall medication withdrawal rate was 34.7%, and it occurred more frequently in patients with cDMARDs only (cDMARDs only, 84.2%; cDMARDs plus biologics, 17.9%; P < 0.001). In the subgroup analysis of patients with cDMARDs plus biologics, patients on biologics tapering with flare-up had a significantly longer time interval between disease onset and initiation of cDMARDs (biologics tapering without flare-up: 0.27 (0.11–0.73) years; biologics tapering with flare-up: 1.14 (0.39–2.02) years; ever withdrawing biologics: 0.26 (0.18–0.42) years, P = 0.0104).Conclusion: Juvenile ERA patients with polyarticular involvement had a higher risk of developing cDMARDs refractory and progressing to biologics use. Patients with a long time interval between disease onset and initiation of cDMARDs were prone to experience flare-up during tapering of biologics.
Highlights
Juvenile spondyloarthritis (SpA) is a distinct entity of chronic pediatric arthritis with characteristics of male predominance, strong association with human leucocyte antigen (HLA)-B27, and involvement of the entheses and axial bones [1]
To further investigate clinical predictors of successful tapering and discontinuation of biological agents, we categorized the patients with conventional disease-modifying anti-rheumatic drugs (cDMARDs) plus biologics into four subgroups based on whether they experienced flare-up during tapering of biologics: not on biologics tapering, on biologics tapering with flare-up, on biologics tapering without flare-up, and ever withdrawing biologics
There were 4 patients who had not been on biologics tapering, 14 on biologics tapering without flare-up, 28 on biologics tapering with flare-up, and 10 ever withdrawing biologics
Summary
Juvenile spondyloarthritis (SpA) is a distinct entity of chronic pediatric arthritis with characteristics of male predominance, strong association with human leucocyte antigen (HLA)-B27, and involvement of the entheses and axial bones [1]. There are seven subtypes of juvenile idiopathic arthritis (JIA), which are classified by the International League of Association for Rheumatology (ILAR) criteria [2]. Juvenile SpA was not one of the seven subtypes, and most juvenile SpA was categorized as enthesitis-related arthritis (ERA) according to the ILAR criteria [1]. Among the seven subtypes of JIA classified by ILAR, ERA is the most common in a large part of eastern and southern Asia, accounting for up to 30% of JIA cases [3, 4]. Oligoarthritis is the most frequent subtype in North American JIA cohorts, while ERA only accounts for 10% of all JIA cases [5]. Possibly because of the relatively low prevalence of ERA in Western countries, limited literature has focused on the outcome and treatment response as well as the medication withdrawal rate in ERA patients [7,8,9]
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