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.

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 B₁₂ 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 B₁₂ deficiency rate was 22.1%. HbA1c, duration of metformin use and metformin dose were independent factors statistically associated with vitamin B₁₂ deficiency.

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.

Ethical Committee of Cho Ray Hospital (approval number 1711/CN-HĐĐĐ)