Routine Vitamin B12 Screening May Prevent Irreversible Nerve Damage

By LabMedica International staff writers
Posted on 05 Dec 2018

The increasing incidence of type-2 diabetes is a serious health issue worldwide. Its prevalence is associated with poor diet and unhealthy lifestyle choices, and it is characterized by high blood glucose levels that need to be controlled by medication.

Nerve damage in the periphery (e.g. face, limbs, and organs) is a common complication of diabetes, with symptoms that range from numbness to pain, and can lead to debilitating loss of balance and co-ordination. Metformin is the recommended and most effective first-line drug for type-2 diabetes but its use has also been linked to vitamin B12 deficiency, which increases the risk of peripheral nerve damage.

Image: Neuropathy is the damage of peripheral nerves; pain and loss of sensation in the extremities and can be caused by diabetes (Photo courtesy of Alnoor Ladhani).

Physicians at the Hucknall Road Medical Centre (Nottingham, UK) conducted an audit of vitamin B12 screening and deficiency among female, metformin-treated, patients with type-2 diabetes at their practice. The audit findings indicated that 64% of patients had not had their vitamin B12 levels checked at all and that 9.6% of patients were deficient but only 6.4% were being treated with vitamin B12. The study findings suggest that earlier detection of vitamin B12 deficiency through routine screening of all metformin-treated, type-2 diabetes patients could reduce their risk of developing irreversible, painful and potentially disabling nerve damage.

Kaenat Mulla, MD, the senior author of the study, said, “Our findings indicate that patients with diabetes taking metformin should be checked more frequently and that we need to ensure deficiencies are adequately treated to avoid irreversible nerve damage. Metformin remains the best treatment for type-2 diabetes, and these findings should not discourage patients from taking it, but encourage doctors to monitor vitamin B12 levels more routinely, so any deficiency can quickly be treated. Current British Society of Haematology guidelines recommend that vitamin B12 levels are checked only when there is clinical suspicion of deficiency. However, peripheral neuropathy is irreversible and it may be too late once symptoms have developed.” The study was presented at the Society for Endocrinology annual conference held November 19-21, 2018, in Glasgow, UK.

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Hucknall Road Medical Centre