Vitamin B12 Deficiency in Type 2 Diabetes Patients Using Metformin

Abstract

Background and aims. Metformin is the first line of medical therapy for type 2 diabetes, the mechanism of metformin remains as yet incompletely understood but recent studies have reported a decrease in vitamin B12 in patients treated with metformin. This study was aimed to evaluate vitamin B12 status in type 2 diabetic patients (T2DM) treated with metformin compared to a control group, and also to evaluate the correlation between the vitamin status and the dose, the frequency of taking metformin, as well as with the age. Methods. This was a cross-sectional study conducted in T2DM patients, 150 patients on metformin and 150 patients without metformin (control group). Vitamin B12 analysed using fully automated modular analyser Roche COBAS e411 Immunoassay system, and Snibe MAGLUMI 2000. Results. The average duration of taking metformin is 10.05 +/- 6.58 years and the average dose is 691.30 +/- 198.41 mg/day. The serum level of vitamin B12 (Cobalamin) is significantly lower in patients taking metformin (216.6 pg/ml versus 555.1 pg./ml, p=0.001). About 31 of 150 diabetic patients on metformin (20.67%) presented a vitamin B12 deficiency (level < 200 pg./ml) versus a 7 without metformin (4.67%). Cobalamin deficiency (rate between 200 and 300 pg/ml) was noted in 50 patients (33.33%) of patients on metformin versus 16 (10.67%) without metformin. The current study reported a relationship between metformin and vitamin B12 deficiency in type 2 diabetic patients. Conclusion. Metformin impacted vitamin B12 levels and our recommendations screening test and treatment modalities should be established due to the widespread use of metformin in T2D patients.