Evaluation of disease severity and treatment responses in patients with enthesitis-related arthritis.

OBJECTIVES

This study evaluated treatment responses to various drugs in patients with enthesitis-related arthritis (ERA) and assessed disease activity indices. Secondary aims included identifying factors influencing biologic use and characterizing clinical features and comorbidities in a regional cohort.

METHODS

We retrospectively reviewed 133 pediatric ERA patients diagnosed between January 2015 and October 2023. Clinical, laboratory, radiological, and treatment data were collected. Disease activity was assessed using JADAS, BASDAI, and JSpADA scores at baseline, month three, and latest follow-up. Statistical analyses identified factors linked to biologic use, comorbidities, and active disease.

RESULTS

The cohort was mostly male (74%) with a median symptom onset age of 12.2 years. HLA-B27 positivity was 53.3%, and axial involvement occurred in 74.4%. Methotrexate was the most frequently used conventional DMARD (71%). According to JSpADA and BASDAI, 41.1% and 49.4% responded to methotrexate, while 47.2% and 58.3% responded to sulfasalazine. Patients treated with biologics had higher remission rates at month three; 60.9% received anti-TNF therapy. Axial involvement, absence of peripheral arthritis, MRI-detected osteitis, and comorbidities predicted anti-TNF use. BASDAI and JSpADA showed better correlation and responsiveness than JADAS. HLA-B27 positive patients had higher ESR and CRP and used systemic steroids more often.

CONCLUSION

Although most patients improved, especially with biologics, axial involvement, early diagnosis, and comorbidities were linked to greater disease burden and need for intensive therapy. Although about half of the patients initially responded to DMARDs, a substantial proportion required biologic therapy for sustained disease control. Therefore, earlier biologic treatment may be considered in patients with poor prognostic factors. BASDAI and JSpADA may be more suitable for monitoring ERA activity. Prospective multicenter studies are needed to confirm these findings and optimize treatment.