Successful Linkage of Electronic Medical Records and National Health Data System in Type 2 Diabetes Research: Methodological Insights and Implications

Purpose: This study assesses success and methodological implications of linking IQVIA's Electronic Medical Records (EMR) of type 2 diabetes (T2D) patients with the National Health Data System (SNDS) database, a cornerstone process in healthcare research. Methods: The OREOT cohort was constituted by T2D patients identified in the IQVIA EMR from 2014 to 2018 and linked indirectly to SNDS database. The EMR database contains clinical records from general practitioner consultations, representing ~2.8% of the French population and the SNDS claims database covers over 99% of the French population's healthcare activities. Linkage success was evaluated by the linkage rate. Baseline patients' characteristics were described for both linked and non-linked patients. Results: Of the 291 408 T2D patients identified in the EMR, 244 656 (84%) were successfully linked. After technical data cleaning, 239 141 (82%) were finally linked. Linked and non-linked patients (n = 52,267) were aged 65 years and more frequently male (57% and 59%); half were obese, and most of comorbidities were consistent. Linked patients had more EMR consultations (median 32 vs 16), and more cardiovascular events (12% vs 7%) or chronic kidney disease (10% vs 7%). Conclusions: The successful linkage of EMR and SNDS databases provides valuable insights for future research in T2D and other chronic diseases requiring clinical data. This study demonstrates the feasibility of such data alignments, particularly in patients with complex health profiles or extensive medical records, and linkage potential to enhance real-world research quality. Despite higher prevalence of baseline comorbidities among linked patients, patients' characteristics were consistent with French T2D population.