Introduction The treatment of type 2 diabetes mellitus (T2DM) is based on preventive hygiene and dietary measures (HDM), oral antidiabetic drugs (OADs), and insulin. The objective of the present study was to reuse general practice data from electronic health records and describe changes over time among patients with T2DM in primary care. Methods We analyzed data on patients with T2DM collected by three family physicians in Tourcoing (France) from 2006 to 2018. Results 403 patients, 1030 treatment sequences, 39,042 appointments, 2440 glycated hemoglobin (HbA1c) measurements, and 9722 wt measurements were included. On inclusion, the mean age was 57.0, the mean weight was 84.4 kg, the mean body mass index was 30.3 kg/m2, and the median HbA1c level was 6.8 % (51 mmol/mol). The patients were following appropriate HDM (40.7 %) and/or were being treated with OADs (54.1 %) or insulin (5.2 %). The median length of follow-up was 3.51 years. Overall, bodyweight was stable for two years during HDM and then increased. The HbA1c level decreased and then increased during HDM, was stable on OADs, and then decreased on insulin.