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Association between vitamin B12 deficiency and metformin use in type 2 diabetic patients: a cross-sectional study in a South Vietnam tertiary hospital

H. H. Phan, An Thuy Thi Nguyen, M. Do

BMJ Open, 2025

5 citations

Abstract

Objectives Vitamin B12 deficiency is a common and neglected adverse effect experienced by type 2 diabetic patients treated with metformin. A lack of vitamin B12 may have severe consequences, such as fatigue, macrocytic anaemia and worsened peripheral diabetic neuropathy. This study aims to identify the rate of vitamin B12 deficiency and the associated factors in type 2 diabetic patients treated with metformin. Design Cross-sectional study. Setting and participants 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 B12 and associated clinical and paraclinical parameters were measured and collected. Results 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 B12 deficiency rate was 22.1%. HbA1c, duration of metformin use and metformin dose were independent factors statistically associated with vitamin B12 deficiency. Conclusions This study identified the rate of vitamin B12 deficiency and associated factors in type 2 diabetic patients treated with metformin. These findings can be helpful in screening patients and replacing vitamin B12 in high-risk populations with vitamin B12 deficiency. Trial registration number Ethical Committee of Cho Ray Hospital (approval number 1711/CN-HĐĐĐ)

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Evidence Hub reads this as a cross-sectional, done in people. Its evidence level is 4 of 5 (Low · observational). Observational designs can show an association but not prove cause.

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