Clinical Features and Risk Factors for Early Bone Destruction in Enthesitis-Related Arthritis: A Cohort Study.

Objectives: To explore the clinical characteristics and identify risk factors for early bone destruction in children with enthesitis-related arthritis (ERA).

Methods: Clinical characteristics were retrospectively analyzed in 85 newly diagnosed cases with ERA at our hospital from January 2019 to December 2021. Logistic regression analyses were performed to identify risk factors for early bone destruction.

Results: In this cohort of 85 ERA patients, early bone destruction was identified in 24.7% (21/85) of cases (ERA-BD group), predominantly affecting the sacroiliac joints (66.7%), knee (14.3%), hip (14.3%), and interphalangeal joints (4.8%). The ERA-BD group exhibited significantly higher rates of polyarticular involvement (≥ 5 joints) compared to the ERA-nBD group (76.2% vs. 12.5%, p < 0.001), with a notably higher incidence of knee joint involvement (66.7% vs. 40.6%, p < 0.05) and sacroiliitis (85.7% vs. 50.0%, p < 0.05). Additionally, the ERA-BD group had a longer disease duration (8.0 vs. 3.5 months, p = 0.009) and elevated C-reactive protein levels (median: 12.3 vs. 4.4 mg/L, p = 0.04). However, no significant differences were observed in ESR or IL-6 levels between the two groups. Multivariate analysis confirmed that polyarticular involvement (OR = 21.39, 95% CI 5.12-89.30) and longer disease duration (OR = 4.06, 95% CI 1.33-12.39) were independent predictors of early bone destruction.

Conclusions: Our study identifies polyarticular involvement (≥ 5 joints) and longer disease duration as key independent predictors of early bone destruction in ERA, highlighting the need for a shift from joint-specific to systemic risk stratification.