Background: Metformin may lead to B12 deficiency and neuropathy. There are no published data on the prevalence of Metformin-related B12 deficiency and neuropathy in the Arabian Gulf.
Aims: Determine whether Metformin intake is associated with B12 deficiency and whether B12 deficiency is associated with diabetic peripheral neuropathy (DPN) and painful diabetic neuropathy.
Methods: Patients with type 2 diabetes mellitus (T2DM) (n = 362) attending outpatient clinics at HMC underwent assessment of B12 levels, the DN4 questionnaire, and vibration perception threshold (VPT).
Results: Comparing Metformin to non-Metformin users there were no differences in B12 levels, VPT, or DN4. The prevalence of B12 deficiency (B12 <133 pmol/l) was lower (P < 0.01) in Metformin (8%) compared to non-Metformin (19%) users. Patients with B12 deficiency had a comparable prevalence and severity of sensory neuropathy and painful neuropathy to patients without B12 deficiency.
Conclusion: Serum B12 levels were comparable between Metformin and non-Metformin users with T2DM in Qatar. T2DM patients on Metformin had a lower prevalence of B12 deficiency. Furthermore, the prevalence and severity of neuropathy and painful diabetic neuropathy were comparable between patients with and without B12 deficiency.
Keywords: diabetic neuropathy; diabetic painful neuropathy; metformin; type 2 diabetes mellitus; vitamin B12 deficiency.