Introduction: Recent studies suggest that long-term use of metformin may decrease the plasma level of Vitamin B12.
Aim: To assess the Vitamin B12 status in Tunisian patients treated with metformin and to study its association with the dose, the duration of metformin use, and the clinical and biological parameters.
Methods: It was a cross-sectional, comparative study on 200 type 2 diabetic (T2D) patients. A vitamin B12 assay was performed with a neurological examination and a Complete blood count.
Results: The mean level of Vitamin B12 assayed in our population was 398.5±188.3 pg/ml. The serum Vitamin B12 levels were 356.9±153.5 pg/ml in the metformin group and 460.9±218.6 pg/ml in the no metformin group (p <0.01). Metformin intake was associated with an increased prevalence of Vitamin B12 deficiency and borderline level. The level of Vitamin B12 was correlated with the duration and the dose of metformin. Vitamin B12 deficiency was significantly associated with anemia, macrocytosis, and diabetic neuropathy. Multivariate analysis concluded that Vitamin B12 deficiency was significantly associated with the duration, cumulative metformin dose, clinical neuropathy, anemia, and macrocytosis.
Conclusion: Our study showed an association of Vitamin B12 deficiency with the dose and duration of metformin intake in Tunisian T2D patients, with hematological and neurological repercussions.