Year : 2026

Volume : Volume 17

Issue : Issue 1

Address for correspondence :
Dr Anoop Kumar
agarwalkdr@gmail.com

Abstract

Background: Metformin is the first-line pharmacotherapy for Type 2 Diabetes Mellitus (T2DM). Emerging evidence suggests a strong association between long-term metformin use and vitamin B12 deficiency, which can lead to hematological and neurological complications. This study aimed to determine the prevalence of vitamin B12 deficiency in T2DM patients on metformin therapy. Materials and Methods: A cross-sectional study was conducted in a tertiary care hospital over six months. A total of 120 T2DM patients who had been on metformin therapy for at least one year were enrolled. Serum vitamin B12 levels were measured. Deficiency was defined as serum B12 < 200 pg/mL, and borderline deficiency as 200-300 pg/mL. Data on demographic characteristics, duration of diabetes, metformin dose, and duration of therapy were collected and analyzed. Results: The mean age of participants was 56.4 ± 9.8 years. The overall prevalence of vitamin B12 deficiency was 25.8% (31/120), while 35% (42/120) had borderline deficiency. Thus, a total of 60.8% of the study population had suboptimal B12 levels. A significant positive correlation was found between the duration of metformin therapy and the prevalence of B12 deficiency (p < 0.01). Patients on a higher daily metformin dose (>1500 mg) had a significantly higher prevalence of deficiency (41.7%) compared to those on a lower dose (≤1500 mg, 15.0%) (p < 0.05). No significant correlation was found with age, gender, or duration of diabetes alone. Conclusion: There is a high prevalence of vitamin B12 deficiency among T2DM patients on metformin therapy in our setting. The deficiency is significantly associated with the duration and dose of metformin. We recommend periodic screening for serum vitamin B12 levels in all T2DM patients receiving long-term metformin therapy to prevent potential complications.