Vitamin B12 Deficiency in Patients with Diabetes on Metformin: Arab Countries

Background: Diabetes is a global pandemic, especially in Arab countries. Aim: The goal of this study was to review the published studies that were conducted to determine the relationship between metformin treatment for type 2 diabetes mellitus (T2DM) and vitamin B12 deficiency and to identify possible complications in this relationship. Methods: I searched for all relevant studies published in English before 2020 on the PubMed and Web of Knowledge databases using the following terms: "metformin", "vitamin B12", "neuropathy", "diabetes mellitus", and Middle Eastern countries. Results: Eleven studies were included in this review which indicated an association between taking metformin and B12 deficiency in patients with T2DM in Arab countries. This B12 deficiency was found to be negatively associated with the dose and duration of metformin therapy. The physician's knowledge of current ADA recommendations regarding supplementation with and screening of the B12 level for T2DM patients on metformin was also found to have an effect. Conclusion: Metformin therapy is associated with B12 deficiency among people with T2DM in Arabic countries. Thus, diabetes must be managed in compliance with current guidelines and recommendations, and B12 levels must be routinely monitored, particularly in those who have been long-term takers of metformin, to ensure the suitable management of diabetes and its complications.