Aims: The significant burden of diabetes requires reliable information collection. While administrative databases are an essential source of information, they have limitations, especially when they are relied upon as the sole data source. This article presents how enriching administrative databases with survey-based data can overcome these limitations and improve knowledge of diabetes. Methods: Based on a random sample of 12,772 people living with diabetes in France, the Entred 3 study complements administrative data with self-reported and medical data, including biological test results. Results: By complementing administrative data with a multi-source approach, we conducted a study on a wider range of diabetes-related topics (e.g., quality of life, health literacy, glycemic control, and individual socio-economic information) for a sample representative of the population treated pharmacologically for diabetes in France, with the data further analyzed by diabetes type. In European France, administrative data were extracted for 8,138 individuals (93.2%) and 3,166 individuals (36.3%) participated in the patient questionnaire. Of these, 1,332 of their physicians also completed a questionnaire (42.1%). Among people living with diabetes, 94.1% had type 2 diabetes, and 5.1% had type 1 diabetes. Conclusion: The real-world data collected in the Entred 3 study provide essential epidemiological, medical, economic, and social information for the development and direction of prevention campaigns aimed at improving medical practices, health status, and quality of life for people living with diabetes. © 2026 The Authors