Prevalence of Vitamin B12 Deficiency in Patients with Type 2 Diabetes Mellitus on Metformin: A Single Retrospective Study in a Tertiary Health Care Center Experience.

Abstract

Introduction: Globally, type 2 diabetes mellitus (T2DM) is a common metabolic disorder affecting millions of people annually. Metformin, a prevalent prescribed antihyperglycemic medication for T2DM, has been associated with vitamin B12 deficiency. This study aimed to determine the prevalence of vitamin B12 deficiency in T2DM patients receiving metformin.

Methods: This retrospective record review study was based on T2DM patients receiving metformin at a single tertiary healthcare center. The prevalence of vitamin B12 deficiency is defined as a serum level <145 pmol/L. Statistical analysis assessed the association between vitamin B12 deficiency and metformin usage.

Results: A total of 246 T2DM patients were included in the study. Among patients who used metformin, 7.7% were found to have vitamin B12 deficiency compared to 4.8% among those who did not use metformin, while the difference was not statistically significant (p=0.571). However, the median (IQR) level of vitamin B12 among metformin users (296 (186)) was significantly lower than that among patients who do not use metformin (382 (370)), p=0.001.

Discussion: The study's findings shed light on the important role of routine screening of vitamin B12 levels in patients on metformin, especially those on long-term use, for early identification and management of deficiency, leading to improved patient outcomes.

Conclusion: Our study revealed a significantly lower level of vitamin B12 among metformin users in T2DM patients. However, the prevalence of vitamin B12 deficiency among metformin users did not differ significantly from those who do not use metformin.