Effect of metformin on vitamin B12 and homocysteine levels among Sudanese with type 2 diabetes mellitus

Abstract

Background: Metformin is the first-line treatment for type 2 diabetes mellitus (T2DM), and hyperglycemia. When taken in high doses or for an extended period, metformin may decrease vitamin B12 (VitB12) level and may increase homocysteine (Hcy) level. There has been no research conducted in Sudan to determine whether metformin has an impact on VitB12 and Hcy levels in individuals withT2DM. The aim of this research is to investigate the effect of metformin on VitB12 and Hcy levels among Sudanese with T2DM. Methods: This cross-sectional study included 98 Sudanese with T2DM who had been taking metformin for at least a year. Data analysis was carried out using SPSS V-26. Results: This study found that 1 patient (1%) had a VitB12 deficiency (< 180 pg/mL), 52 (53.1%) subjects had a normal VitB12 level (180 - 900 pg/mL), and 45 (45.9%) subjects had VitB12 ≥ 900 pg/mL. One patient (2.9%) had an Hcy deficiency (< 3µmol/l) and 34 (97.1%) subjects had a normal Hcy level (3–15 µmol/L). The study showed a, significant negative correlation between VitB12 and vitamin supplements (P = 0.003) and metformin combined with insulin (P = 0.000). Although that belongs to the subgroup that took vitamin supplements, there was a significant positive correlation between VitB12 and metformin alone (P = 0.006) and a significant negative association with metformin combined with insulin (P = 0.000). In the subgroup that did not take vitamin supplements, there was a significant positive correlation between VitB12 and FBS (P = 0.001). There was an insignificant correlation between VitB12 and the metformin dose and use duration. The correlation between VitB12 and Hcy levels was insignificant in the entire group and in both subgroups. The correlation between Hcy levels and metformin use duration was significantly negative (P = 0.015), but the correlation between Hcy levels and metformin dose was insignificant. Conclusions: In Sudanese with T2DM and under metformin treatment, serum VitB12 level was positively and significantly correlated with DM duration and (FBS), was significantly and negatively correlated with vitamin supplements. On the conversely, serum homocysteine (Hcy) levels significantly decreased with metformin use duration.