JMIR Publications

ABSTRACT

Background:

Rare eye diseases are characterized by low prevalence, clinical heterogeneity, and fragmented data collection, which limit statistical power and multicenter research. In France, the development of health data warehouses (HDWs) is regulated under the French Health Data Warehouse framework, which imposes strict requirements for governance, security, and interoperability. While national and European initiatives aim to harmonize rare disease data, disease-specific operational implementation remains challenging.

Objective:

To describe the design, regulatory implementation, and early operational outcomes of FREDD (French Rare Eye Diseases Database), a national HDW dedicated to rare eye diseases, and to analyze key success factors, bottlenecks, and sustainability considerations associated with its deployment.

Methods:

FREDD was developed as a centralized HDW compliant with French regulations. Its dataset was structured around the minimum rare disease dataset, ensuring compatibility with the French rare disease databases, and aligned with the European datasets to maximize semantic interoperability. The infrastructure implements a three-layer architecture (data collection, processing, and research reuse), structured electronic case report forms with embedded validation rules, dedicated imaging harmonization pipelines, and centralized data quality monitoring tools. Governance was formalized through a steering committee and a scientific and ethical committee, with strictly controlled data access procedures.

Results:

Regulatory authorization was obtained in April 2024, and the full infrastructure became compliant with CNIL Health Data Warehouse requirements in November 2025. Data collection began earlier, in March 2025, enabling patient inclusion across five SENSGENE pilot centers. Within the first year, over 1600 patients and 10000 imaging datasets were integrated, demonstrating rapid adoption and scalability. Data collection combined retrospective imports and prospective entry, supported by FREDDEX, which enabled pre-filling of ~30% of clinical data from BaMaRa. High data quality was ensured through automated controls and centralized monitoring, with an overall inconsistency rate of ~7%, mainly reflecting logical dependencies. Approximately 40% of patients had associated imaging data, processed through a standardized and secure pipeline.

Conclusions:

The FREDD initiative illustrates that a disease-specific HDW can be successfully implemented in a highly regulated environment when regulatory compliance, governance, and technical architecture are addressed in parallel. Establishing FREDD required substantial institutional investment, yet early operational outcomes indicate strong potential for scalability. Moving forward, sustainability will depend on actively leveraging the database through multicenter research, high impact studies, and reinforced interoperability with European infrastructures to unlock the full scientific and clinical value of rare eye disease data over the long term.