Association of Vitamin B12 and Metformin in Type II Diabetes Patients in Bahrain

Objective: Metformin therapy is the gold standard treatment for type 2 diabetic patients. Long term use of metformin has been associated with vitamin B12 deficiency. We aimed to study the level of vitamin B12 in type 2 diabetic patients on metformin, and to determine other factors affecting the level of vitamin B12. Methodology: Out of 344 patients with type 2 diabetes that were interviewed from January to December 2015; 304 (91.3%) were investigated for vitamin B12 levels deficiency. The patient’s lab results from 2015-2016 were reviewed from the electronic hospital information system, patient data file. Result: Most of the patients, 56.4% had a normal vitamin B12 level. In 91% of the patients the treating physician had already investigated for serum vitamin B12 level. Dyslipidemia and hypertension were significantly more (p=0.009 and 0.022 respectively) in patients with normal vitamin B12 level. Percentage of normal B12 level patients was higher (p=0.001)even in more than 20 years of metformin use; 46.7% of more than 20 years Metformin users had vitamin B12 level within 301-450 pg/mL and 33.3% had more than 450 pg/mL. Conclusion: We recommend routine screening for basal vitamin B12 level for all patients with type 2 diabetes mellitus (T2DM) at the initiation of metformin therapy with subsequent annual follow up of the level.