The role of Helicobacter pylori in vitamin-B12 deficiency due to metformin use

Abstract

Background: Metformin is widely used for the treatment of type-2 diabetes (T2D) but was shown to cause vitamin-B12 deficiency. H pylori infection was also suggested to cause vitamin-B12 deficiency. This study aimed to elucidate the relationships in this triad by investigating vitamin-B12 deficiency and H pylori infection in T2D patients using metformin. Materials and Methods: This descriptive cross-sectional study recruited T2D patients using metformin from a primary care center and examined their socioeconomic status, accompanying complaints, medication use, and hemogram parameters such as serum vitamin B12, calcium, and hemoglobin. The presence of H pylori infection was determined through stool antigen test. Results: Study included 421 T2D patients on metformin regimen: 213 (50.6%) males and 208 (49.4%) females. The mean duration of diabetes was 9.88 ± 7.32 years, and the total metformin dose was 1925.5 ± 236.7 mg/d. Almost half of the participants (n = 199, 47.3%) had H pylori infection, and more than half (n = 222, 52.7%) had vitamin-B12 deficiency. The rate of vitamin-B12 deficiency was significantly higher among those with H pylori infection. No significant relationship was found between the daily metformin dose and vitamin-B12 deficiency. Conclusions: This study supported the role of H pylori infection in vitamin-B12 deficiency. However, the effects of increased metformin dose and H pylori infection on vitamin-B12 levels were not additive. It is recommended that vitamin-B12 levels in T2D patients are monitored and those with vitamin-B12 deficiency, regardless of metformin dose, are screened for H pylori and, if necessary, treated.