People with type 2 diabetes who take metformin should have their vitamin B12 levels regularly assessed to monitor any signs of nerve damage, research indicates.
The recommendation comes following a study by Nottingham researchers who stressed the importance of early detection of peripheral neuropathy to catch symptoms and prevent further damage.
In a review of women from a health centre in Nottingham, which involved auditing B12 levels among women with type 2 diabetes who were taking metformin, the researchers found 64% had not had their vitamin B12 levels checked.
A total of 9.6% reviewed were shown to be deficient in vitamin B12, but only 6.4% were being given the vitamins they needed.
Study author Dr Kaenat Mulla from Hucknall Road Medical Centre said: “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.”
Metformin, a common type 2 diabetes drug, has previously been linked to vitamin B12 deficiency, but Dr Mulla stressed her warning is not meant to discourage people prescribed metformin from taking the drug.
“Metformin remains the best treatment for type 2 diabetes, 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.”
Dr Mulla’s team now plan to further investigate the best way to treat people who have decreased vitamin B12 levels and to continue gathering evidence to support why they think people with type 2 diabetes on metformin should be screened at their annual check-up.
“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.”
The findings were unveiled recently at the Society for Endocrinology’s annual conference in Glasgow.