Özen, Seza

Objective To develop and validate classification criteria for pediatric chronic nonbacterial osteomyelitis (CNO) jointly supported by EULAR and the American College of Rheumatology (ACR). Methods This international initiative had 4 phases: (1) candidate items were proposed in a survey of pediatric rheumatologists, (2) criteria definition and reduction by Delphi and nominal group technique exercises, (3) criteria weighting using multicriteria decision analysis, and (4) refinement of weights and threshold score in a development cohort of 441 patients and validation in another cohort of 514 patients. Results The new EULAR/ACR classification criteria for CNO require typical radiographic or magnetic resonance imaging findings and bone pain as an obligatory entry criterion and exclusion criteria of malignancy, infection, vitamin C deficiency, and hypophosphatasia, followed by additive weighted criteria in 5 clinical (site of bone lesions, pattern of bone lesions, age at onset, coexisting conditions, fever) and 4 pathology/laboratory domains (bone biopsy findings if done, anemia, C‐reactive protein level, and erythrocyte sedimentation rate). A total score ≥55 is required for classification as CNO. The new criteria had a sensitivity of 82% and specificity of 98% in the validation cohort. Conclusion These new classification criteria for pediatric CNO developed with international input reflect current views about CNO, have high specificity and good sensitivity, and provide a key foundation for future CNO research.

Objective We describe the demographics, clinical features, disease course, and survival of polyarteritis nodosa (PAN) through an international collaboration (GLOBAL‐PAN). Methods Patients with PAN were recruited between 1990 and 2020 from observational cohorts of nine countries across Europe, Japan, and North America. Eligibility was retrospectively defined using the European Medicines Agency classification algorithm. Patients with PAN related to hepatitis B virus (n = 12) and two monogenic diseases mimicking PAN, deficiency of adenosine deaminase 2 enzyme (n = 16) or familial Mediterranean fever (n = 11), were excluded. Data regarding organ involvement, relapse, disease‐related damage, and survival were analyzed. Results Three hundred fifty‐eight patients (female:male ratio 174:184), including those with systemic PAN (sPAN, n = 282) and cutaneous PAN (n = 76), were included. Twenty‐five were pediatric onset. Mean ± SD age at diagnosis was 44.3 ± 18.1 years. Constitutional symptoms (71.5%), cutaneous involvement (70.5%), musculoskeletal findings (69.1%), and neurologic features (48.0%) were common manifestations. Among patients with sPAN, gastrointestinal involvement and proteinuria over 400 mg/day were reported in 52.2% and 11.2%, respectively. During a median (interquartile range) 59.6 (99.5) months of follow‐up, relapse occurred in 48.5% of patients. One, 5‐ and 10‐year survival rates for sPAN were 97.1%, 94.0%, and 89.0%, respectively. Predictors of death for sPAN included age ≥65 years at diagnosis, serum creatinine at diagnosis >140 μmol/L, gastrointestinal manifestations, and central nervous system (CNS) involvement. Conclusion The spectrum of PAN remains a complex, multifaceted disease. Relapse is common. Age ≥65 years and serum creatinine >140 μmol/L at diagnosis, as well as gastrointestinal and CNS involvement, are independent predictors of death in sPAN. image