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Copyright ©The Author(s) 2025.
World J Diabetes. Jul 15, 2025; 16(7): 107514
Published online Jul 15, 2025. doi: 10.4239/wjd.v16.i7.107514
Table 1 Clinical guideline recommendations on metformin-induced vitamin B12 deficiency
Guideline
Recommendation
Monitoring frequency
Treatment
Ref.
British Committee for Standards in HaematologyDoes not recommend routine screening, but suggests evaluation if clinical suspicion exists; highlights the importance of ruling out pernicious anemiaNot specifiedIf due to metformin: Oral cobalamin 50 μg/day for 1 month; prophylactic supplementation not recommended[46]
American Association of Clinical Endocrinologists and American College of Endocrinology-Clinical Practice Guidelines-2015Mentions the risk of deficiency in metformin usersNot specifiedNo treatment specified[40]
Diabetes CanadaDoes not mention vitamin B12 deficiencyNot mentionedNot mentioned[42]
Diabetes Research and Clinical Practice-2023Mentions vitamin B12 only as a differential diagnosisNot mentionedNot mentioned
Vitamin B12 deficiency in over 16 seconds: Diagnosis and management, guidance NICERecommend screening in patients with at least one symptom and one risk factor (such as metformin use)Not specifiedOral or IM vitamin B12; reevaluate after 3 months; consider discontinuing metformin if it is the cause[38]
ADA Standards of Care in Diabetes-2025Acknowledges the risk of deficiency in patients with neuropathy or anemia, especially those taking > 1500 mg/day or using it for > 4-5 yearsPeriodic monitoring recommended, no specific interval definedNo specific treatment recommended[39]