More regular checks of vitamin B12 levels in patients with type 2 diabetes could help prevent irreversible and debilitating nerve damage, according to a new study by a Nottingham GP practice.
The findings, presented at the Society for Endocrinology’s annual conference in Glasgow, make the case for routine screening of all patients with type 2 diabetes who are treated with the drug metformin in order to reduce the risk of painful and potentially disabling nerve damage.
“Our findings indicate that patients with diabetes taking metformin should be checked more frequently”
Peripheral nerve damage – or neuropathy - in the face, limbs and organs is a common complication of diabetes with symptoms ranging from numbness to pain and a risk of potentially debilitating loss of balance and co-ordination.
Metformin is the recommended and most commonly used drug for treating type 2 diabetes but has been linked to vitamin B12 deficiency, which increases the risk of peripheral nerve damage.
However, there are no official guidelines on checking vitamin B12 levels in patients treated with the drug.
The study saw Dr Kaenat Mulla and GP colleagues at Hucknall Road Medical Centre in Nottingham look at vitamin B12 screening and deficiency in female patients with type 2 diabetes who were on metformin.
Their research found nearly two thirds – 64% - of patients had not had their vitamin B12 levels checked at all.
Meanwhile, 9.6% were found to have a vitamin B12 deficiency but only 6.4% were being treated with vitamin supplements.
Dr Mulla said the results showed that routine vitamin B12 screening for this group of patients could help spot issues before it was “too late”.
“Current British Society of Haematology guidelines recommend that vitamin B12 levels are checked only when there is a clinical suspicion of deficiency,” she said. “However, peripheral neuropathy is irreversible and it may be too late once symptoms have developed.”
The research team now plan to extend their audit to look at how best to treat patients found to have a vitamin B12 deficiency.
They hope this will provide more evidence that all type 2 diabetes patients taking metformin should have their vitamin B12 levels assessed regularly - such as 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,” said Dr Mulla.
However, she also stressed that metformin was an effective treatment for type 2 diabetes and patients should continue taking it.
“Metformin remains the best treatment for type 2 diabetes,” she said. “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.”