Successful linkage of French large-scale national registry populations to national reimbursement data: Improved data completeness and minimized loss to follow-up

Abstract

Registries, a cornerstone of contemporary medicine, frequently suffer from incomplete documentation and losses to follow-up. By linking data to a single-payer national claims database, national registries may be enriched and the quality enhanced. To explore the value of data from the French Système National des Données de Santé (SNDS) as a resource to enhance the quality of registries when combined with data from electronic case report forms, and to assess the power to minimize data gaps and losses to follow-up. A probabilistic algorithm was developed to link and match records in the SNDS with patient data from the electronic case report forms of two registries on transcatheter aortic valve implantation: FRANCE-2 and FRANCE-TAVI. The algorithm created patient profiles from transcatheter aortic valve implantation procedures in the SNDS, matching them as closely as possible to the profiles in the registry databases. The objective was to achieve 90% linkage of the populations. The linked database was analysed for completeness and loss to follow-up. For validation, mortality curves for the linked registry cohorts were compared with those for the original populations. A total of 34,397 unique registries entries were identified, and 89.9% of patients in the SNDS could be linked. Rates of losses to follow-up over 2 years were 1.0% in the linked FRANCE-TAVI population compared with 40.3% based on electronic case report form documentation. For FRANCE-2, 3-year rates of losses to follow-up were 1.7% and 6.1%, respectively. Mortality curves for populations based on SNDS and electronic case report form data were practically superimposable. Linking data from a single-payer national claims database to national registries using a probabilistic approach is feasible and can close data gaps and practically abolish losses to follow-up in the registry population.