Serum Vitamin B12 Level in Type 2 Diabetes Patients on Metformin Therapy

Background and Objective: Type 2 diabetes mellitus is a common non-communicable disease all over the world. Metformin is an effective treatment option for diabetic patients. However, this option is frequently accompanied by vitamin B12 deficiency. Therefore, we aimed to measure the prevalence of serum vitamin B12 deficiency in type 2 diabetic patients and recognize risk factors related to vitamin B12 deficiency. Methods: This study was a retrospective cross-sectional study implemented in Layla Qasim Diabetic Center in Erbil city-Kurdistan region/Iraq through six months from 1st of October 2023 to 31st of March 2024 on a sample of 100 type 2 diabetic patients. We investigated and analyzed patients' data. The vitamin B12 deficiency was diagnosed regarding the center laboratory cutoff value of less than 191 pg/ml. Results: The mean serum B12 level of type 2 diabetic patients was (421.9 pg/ml); 21% had low serum B12 levels. A significant association was observed between good glycemic control (i.e. HbA1c of less than 7.0%)1 of type 2 diabetic patients and low serum B12 level (p-value=0.04). No significant relationships existed between serum B12 levels and other type 2 diabetic patients' characteristics (p>0.05). Conclusions: The prevalence of serum vitamin B12 deficiency among type 2 diabetic patients on metformin is within the acceptable range (i.e. serum vitamin B12 between 191-663 pg/ml). The strict glycemic control by high doses of metformin therapy for type 2 diabetic patients commonly leads to serum vitamin B12 deficiency.