Assessment Of Serum Vitamin B-12 And Folate Levels And Macrocytosis In Patients With Type 2 Diabetes Mellitus On Metformin Attending Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia: A Cross-Sectional Study

Background: Metformin is the first-line drug in the treatment of type 2 diabetes mellitus. Monitoring vitamin B-12 deficiency associated with long-term and high-dose therapy is not a common practice in many clinical settings in Ethiopia.Objective: The study aimed to measure levels of serum vitamin B-12 and folate and to assess the macrocytic status of type 2 diabetes mellitus patients on metformin.Methods: A cross-sectional study was conducted on 80 type 2 diabetes mellitus patients who had been on metformin for 5 months or more at the diabetic clinic of Tikur Anbessa Specialized Teaching Hospital. Serum vitamin B-12 and folate levels were quantified by chemiluminescent immunoassays. Mean corpuscular volume was determined by complete blood count. Differences in vitamin B-12 and folate levels and mean corpuscular volume between different groups were assessed using Kruskal-Wallis H and Mann-Whitney U tests.Results: Vitamin B-12 and folate deficiency were documented in 5% and 23.8% of participants, respectively, and 6.2% of patients were macrocytic. Levels of vitamin B-12 and folate in patients who had been on metformin >1,500 mg/day >= 4 years were significantly lower those who had been on metformin 1,000-1,500 mg/day and <1,000 mg/day <4 years, respectively.Conclusion: Low serum vitamin B-12 and folate levels and macrocytosis were found to be associated with prolonged metformin treatment.y