Serum vitamin B12 and folate levels and, macrocytosis in patients with type 2 diabetes mellitus on metformin attending Tikur Anbassa Specialized Hospital
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Date
2020-04
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Addis Ababa University
Abstract
Introduction:-Metformin is an orally administered drug used for lowering blood glucose concentrations in patients with type 2 diabetes mellitus. However, its long term and high dose therapy is associated with vitamin B12 malabsorption. Furthermore, screening and monitoring of vitamin B12 level of patients with metformin is not a common practice.
Objective of the study:- Aim of this study was to measure serum vitamin B12 and folate levels and, to assess macrocytic status of type 2 diabetes mellitus patients who were on metformin treatment.
Methodology:- Hospital based cross-sectional study was used as an appropriate study design for this particular study. Serum vitamin B12 and folate levels and, MCV were determined using COBAS 6000 immunoassay analyzer and UniCel DxH 800 analyzer (Beckman Coulter, USA) respectively in 80 type 2 diabetes mellitus patients who had been on metformin for 5 months or more. Differences in vitamin B12 and folate levels and, MCV between different groups were assessed based on daily dose and duration of metformin intake using Mann- Whitney U and Kruskal- Wallis H tests, and P <0.05 was considered as statistically significant.
Result:-Serum vitamin B12 and folate values below the lower reference limits were documented in 5% and 23.8% of type 2 diabetes mellitus patients respectively, and 6.2% of patients had MCV values above the higher reference limit. The median level of vitamin B12 in patients who were on metformin at a dose of >1500 mg/ day for ≥ 4 years was significantly lower (p< .001) compared to patients who were on metformin at a dose of 1000-1500 mg/day and < 1000mg/day for < 4 years respectively. Insignificantly higher value of MCV was recorded among high dose and long duration of metformin takers. The median level of folate in patients who were on metformin at a dose of >1500 mg/ day for ≥ 4 years was significantly lower compared to patients who were on metformin at a dose of 1000-1500 mg/day and < 1000mg/day for < 4 years respectively (p= 0.002 for dose; and p=0.010 for duration).
Conclusion:- Type 2 diabetics with longer duration and higher dose of metformin intake were found to have lowered serum vitamin B12 and folate levels. Thus, monitoring vitamin B12 status of type 2 diabetics on higher and prolonged duration of metformin treatment would have a beneficial impact in minimizing complications that could be worsened due to metformin.
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Anemia, Diabetic peripheral neuropathy, Folate, Homocysteine, Vitamin B12.