How Well Do the New EULAR/ACR Classification Criteria Capture Pediatric Chronic Nonbacterial Osteomyelitis? A...

Area of Science:

• Rheumatology
• Pediatric Rheumatology
• Autoinflammatory Diseases

Background:

• Chronic nonbacterial osteomyelitis (CNO) is a rare, challenging autoinflammatory bone disorder lacking specific biomarkers.
• Diagnosis is complicated by heterogeneous presentations and the need for validated classification criteria.

Purpose of the Study:

• To systematically validate the performance of the new European Alliance of Associations for Rheumatology (EULAR) and American College of Rheumatology (ACR) classification criteria for pediatric CNO.
• To compare the EULAR/ACR criteria against the established Bristol criteria using expert clinical diagnosis as the reference standard.

Main Methods:

• A retrospective, multicenter cohort study involving 114 children with CNO and 116 controls.
• Systematic collection of demographic, clinical, laboratory, imaging, and biopsy data.
• Assessment of participants using both EULAR/ACR and Bristol criteria, with statistical analysis including sensitivity, specificity, and ROC analysis.

Main Results:

• The EULAR/ACR criteria showed higher sensitivity (97.4%) and comparable specificity (81.0%) versus Bristol criteria (79.8% sensitivity, 80.2% specificity).
• EULAR/ACR criteria demonstrated a lower negative likelihood ratio (0.03 vs. 0.25), indicating superior rule-out capacity.
• The EULAR/ACR criteria effectively identified atypical CNO phenotypes (unifocal, nonclavicular) and showed substantial agreement (κ=0.66) with Bristol criteria.

Conclusions:

• The EULAR/ACR criteria provide a more sensitive, inclusive, and specific framework for classifying pediatric CNO.
• These criteria may expedite diagnosis, reduce unnecessary biopsies, and improve the identification of diverse CNO presentations.
• Clinical judgment remains crucial for differentiating CNO from overlapping inflammatory conditions.