Coding systems and monitoring practices across the ERN ReCONNET: insights from a comprehensive survey and unmet needs

Background: Rare and complex connective tissue diseases (rCTDs) pose significant challenges for healthcare systems due to the lack of standardized approaches for recording and monitoring patient data. The European Reference Network on Rare and Complex Connective Tissue and Musculoskeletal Diseases (ERN ReCONNET) aims to harmonize patient data recording practices across member centres. This study evaluates current practices and unmet needs related to coding systems and monitoring. Methods: A cross-sectional study design was employed, involving three phases. The first phase, mapped the unmet needs for coding systems and monitoring practices across ERN ReCONNET centres. The second phaseprioritized these unmet needs, and the third phase aimed at defining action points to address those unmet needs by means of a Level of Agreement. We conducted a web‑based survey among ERN ReCONNET centres to evaluate current practices(response rate 75.0% [48/64] in Phase 1); and an additional inquiry in Phase 2 (58 responders) to identify the unmet needs of the Network. Data were analysed using descriptive statistics. Results: The initial survey included responses from 48 centres. About 42% of the centres used some form of paper-based records, and only 25% used dedicated biobank software. ICD-10 was predominantly applied for coding diagnoses, sub-diagnoses, and comorbidities, while ORPHAcodes were also employed, though less frequently. Clinicians were primarily responsible for data collection and submission, leading to significant administrative burden. The second survey, with 58 respondents, identified the lack of adoption of ORPHAcodesand the heterogeneity in coding systems as top unmet needs. Additionally, the survey highlighted the significant burden on clinicians and the need for improved information technology(IT) infrastructure to facilitate data extraction for ERN yearly monitoring. Lastly, 7 action points were identified in order to plan tangible actions to address the unmet needs of the rCTDs community. Conclusion: This study highlights the heterogeneity in data documentation practices, coding system usage, and monitoring activities across ERN ReCONNET centres. The findings underscore the need for standardization and optimization of data management processes. Addressing these challenges through digitalization and standardized coding practices is essential for realizing a truly integrated and collaborative network for rare connective tissue diseases across Europe. Supplementary information: The online version contains supplementary material available at 10.1186/s13023-026-04304-7.