Vitamin B12 deficiency and clinical neuropathy with metformin use in type 2 diabetesAuthor(s): Irfan Ahmad Mir
Type 2 diabetes, which is more prevalent (more than 90% of all diabetes cases) and the main driver of the diabetes epidemic, now affects 5.9% of the world’s adult population with almost 80% of the total in developing countries. Currently, 422 million people worldwide are suffering from diabetes. In India, reports show that 69.2 million people are living with diabetes (8.7%) as per 2015 data. Long-term metformin treatment is a known pharmacological cause of vitamin B12 deficiency, as was evident within the first 10-12 years after it started to be used. This was a cross-sectional study conducted in the Postgraduate Department of Medicine at S.M.H.S. Hospital. A total of 700 consecutive patients with type 2 diabetes were taken for the study. Type 2 diabetic patients were divided into two groups: those taking metformin, and those who were not taking metformin. Cumulative metformin doses were recorded in patients taking metformin using their dose and duration of treatment history. Serum vitamin B12 levels were done in all patients. All the included patients were subjected to a vitamin B 12 assay. Based on the results of B12 levels, patients were classified into the normal level, possible B12 deficiency, and definite deficiency. In our study, we found that metformin use is associated with Vitamin B12 deficiency, dependent upon the cumulative dose of metformin. Importantly prolonged metformin use is also associated with an increase in the prevalence of clinical neuropathy.