Association between vitamin B<sub>12</sub> deficiency and metformin use in type 2 diabetic patients: a cross-sectional study in a South Vietnam tertiary hospital.

Phan, Hen Huu; Nguyen, An Thuy Thi; Do, Minh Duc · BMJ Open · 2025

cross_sectional · Level IV

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Abstract

Vitamin B<sub>12</sub> deficiency is a common and neglected adverse effect experienced by type 2 diabetic patients treated with metformin. A lack of vitamin B<sub>12</sub> may have severe consequences, such as fatigue, macrocytic anaemia and worsened peripheral diabetic neuropathy. This study aims to identify the rate of vitamin B<sub>12</sub> deficiency and the associated factors in type 2 diabetic patients treated with metformin. Cross-sectional study. This study involved 145 type 2 diabetic patients treated with metformin in Cho Ray hospital, a tertiary healthcare centre in South Vietnam. The levels of vitamin B<sub>12</sub> and associated clinical and paraclinical parameters were measured and collected. The study population's mean age was 61.5 years, of which 51.7% were women. The median duration of metformin use was 10 years, and the median metformin dose was 1700 mg. The vitamin B<sub>12</sub> deficiency rate was 22.1%. HbA1c, duration of metformin use and metformin dose were independent factors statistically associated with vitamin B<sub>12</sub> deficiency. This study identified the rate of vitamin B<sub>12</sub> deficiency and associated factors in type 2 diabetic patients treated with metformin. These findings can be helpful in screening patients and replacing vitamin B<sub>12</sub> in high-risk populations with vitamin B<sub>12</sub> deficiency. Ethical Committee of Cho Ray Hospital (approval number 1711/CN-HĐĐĐ).

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