小児慢性非細菌性骨髄炎における治療変更の予測因子としてのベースライン骨密度：実世界コホート研究

To assess whether baseline bone mineral density (BMD) influences treatment response and predicts the need for treatment switching in patients with chronic nonbacterial osteomyelitis (CNO).

Demographics and clinical characteristics of patients, 25-OH vitamin D levels, radiologic findings (dual-energy X-ray absorptiometry, magnetic resonance imaging), and treatment switching were evaluated. First, patients were divided into 2 groups based on their treatment options: group 1 (NSAIDs/cDMARDs) and group 2 (TNFi/bisphosphonates). In addition, predictive factors for treatment switching were identified through binary logistic regression analysis in patients evaluated by DEXA.

Ninety-one patients (females, 54.9%) with CNO were included. BMD was analyzed in 48 (52.7%) patients and was normal in 20 (41.6%), osteoporotic in 19 (39.6%), and osteopenic in 9 (18.8%). Overall, 42 (68.9%) patients had vitamin D insufficiency/deficiency. In group 1 (n=10), none of the patients had osteoporosis, 3 (30%) had osteopenia, and 7 (70%) had normal BMD results, whereas in group 2 (n=38), 19 (50%) had osteoporosis and 6 (15.7%) had osteopenia (p=0.016). Multivariate logistic regression analysis revealed that osteoporosis (OR=7.685, 95% CI: 1.679-26.562, p=0.009) and axial involvement (OR=2.625, 95% CI: 1.751-13.069, p=0.034) were the predictive factors for the treatment switching.

Patients with normal BMD were more likely to respond well to first-line treatment. Osteoporosis and axial involvement are predictive factors for therapy switching in refractory disease. Although vitamin D deficiency is common in our cohort, its effect on relapse was not found. Monitoring of osteoporosis may be critical in the selection of second-line treatment.