Rare disease care pathways profile in France: leveraging hospital big data to characterize natural history in osteogenesis imperfecta

Abstract Rare bone disease referral centers (RBDCs) were established to improve the diagnosis and management of rare diseases. The objective of this retrospective observational study was to characterize real-life care pathways of patients with osteogenesis imperfecta (OI) in the Paris region. Patient data were extracted from the Assistance Publique-Hôpitaux de Paris (AP-HP) health data warehouse (Entrepôt de Données de Santé). Patients were identified using the ICD-10 code for OI (Q78.0) and keyword searches. Inclusion criteria were age ≥15 yr and at least one hospital visit between January 1, 2016 and March 1, 2021. After exclusion of unconfirmed diagnoses and patients younger than 15 yr, 472 patients with OI were included (mean age 39.5 ± 16.2 yr; 64.6% women). Of these patients, 78% (N = 368) were cared for in one of Paris RBDC, the majority in a single center (76% (N = 280)), while 104 patients (22%) were not seen within RBDCs in AP-HP data. The most frequent specialties involved were rheumatology (74.9%, N = 326), orthopedics (17.6%, N = 76), and otorhinolaryngology (12.9%, N = 56). The proportion of patients seen in rheumatology increased after the transition age of 25 yr (81.8% before vs 90% after, p = .04), whereas consultations in orthopedics and genetics decreased (29.5% vs 17.8%, p = .02, and 22.7% vs 6.8%, p < .0001, respectively). Orthopedic surgery during follow-up was performed in 6.2% of patients followed in RBDCs and 8.6% of those not seen within RBDCs. Although 78% (N = 368) of patients with OI in the Paris region were followed within RBDCs, nearly one quarter were not (22%), suggesting persistent gaps in access to specialized care. These findings provide a real-life description of hospital-based care pathways for OI but do not allow assessment of the effectiveness of the referral center model.