Vitamin B-12 deficiency in type 2 diabetes patients on metformin therapy – A narrative review

Abstract

Due to its increased incidence and related complications, T2DM (Type 2 diabetes mellitus) is becoming an issue of public health concern. This narrative review elucidates association between metformin therapy in T2DM and cobalamin (Vit. B12) deficiency. According to various studies, diabetic patients receiving metformin medication had a higher risk of Vit. B12 (vitamin B12) deficiency than those T2DM patients not receiving metformin therapy, ranging from 14% to 22.4% in those taking metformin and from 6% to 10% in those not taking metformin. Odds ratios for Vit. B12 deficiency associated with using metformin ranged from 2.2 to 2.7, indicating a moderate to high risk. The management of Vit. B12 deficiency in T2DM involves a combination of accurate diagnosis, appropriate supplementation strategies, patient education, and interdisciplinarycollaboration. Consensus and guidelines recommend routine monitoring of serum vitamin B12 levels, high-dose oral supplementation, intramuscular injections for severe deficiency, and consideration of alternative routes of administration, along with lifestyle modifications. Keywords: Diabetes mellitus type 2, Metformin therapy, Vitamin B12, Management, and treatment