Metformin Use Is Not Associated With B(12) Deficiency or Neuropathy in Patients With Type 2 Diabetes Mellitus in Qatar

BACKGROUND: Metformin may lead to B(12) deficiency and neuropathy. There are no published data on the prevalence of Metformin-related B(12) deficiency and neuropathy in the Arabian Gulf. AIMS: Determine whether Metformin intake is associated with B(12) deficiency and whether B(12) 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 B(12) levels, the DN4 questionnaire, and vibration perception threshold (VPT). RESULTS: Comparing Metformin to non-Metformin users there were no differences in B(12) levels, VPT, or DN4. The prevalence of B(12) deficiency (B(12) <133 pmol/l) was lower (P < 0.01) in Metformin (8%) compared to non-Metformin (19%) users. Patients with B(12) deficiency had a comparable prevalence and severity of sensory neuropathy and painful neuropathy to patients without B(12) deficiency. CONCLUSION: Serum B(12) levels were comparable between Metformin and non-Metformin users with T2DM in Qatar. T2DM patients on Metformin had a lower prevalence of B(12) deficiency. Furthermore, the prevalence and severity of neuropathy and painful diabetic neuropathy were comparable between patients with and without B(12) deficiency.