SUN-695 Should Vitamin B12 Status Monitoring Be Implemented for Patients Taking Metformin?

Abstract

Introduction: Cobalamin (vitamin B12) is used in multiple metabolic processes, functioning primarily as a coenzyme with Methylmalonyl-CoA mutase and Methionine synthase in humans. Without functioning enzyme, substrate levels build up which are neurotoxic, leading to neurological debilitation. Lack of enzyme also halts cellular replication processes causing severe anemia. Since numerous studies have found decreased cobalamin levels in patients who regularly take metformin1, then could regular monitoring of cobalamin levels in such patients prevent these outcomes? Case Presentation: We present a 50-year-old female who reported to the ED with general weakness and shortness of breath after having a seizure. Her medical history included type 2 diabetes mellitus being treated with metformin and a history of seizures controlled by carbamazepine since childhood.Neurological exam abnormalities consisted of DTRs that were 1/4 on all proximal and distal upper and lower extremities and absent fine sensory and vibratory sensation on ankles and feet bilaterally. Patient was also ataxic. Hgb A1c was 14%. Head CT, chest x-ray, EKG, and cardiac markers found no abnormalities. CBC found a profound pancytopenia with WBC 1.6, RBC 1.27, Hgb 5.2, MCV 119, MCH 40.9, MCHC 34.3, RDW 18.2, and platelets 113. Blood smear was normal. Bone marrow sample showed normochromic macrocytic cells with no other abnormalities. Folate level was normal and cobalamin was found to be low (61.5 pmol/L). Intrinsic factor antibodies were negative. Extensive autoimmune workup was also negative. Discussion: Our patient’s neurological symptoms and pancytopenia were found to be due to multiple factors. R. Pawlak, found that metformin use had a 2.45 (p < 0.0001) times higher odds of developing B12 deficiency in comparison to non-metformin users1. This was also supported by a systemic review of the impact of metforminCarbamazepine is known for its effects on decreasing the absorption of folate and has statistically been found to decrease cobalamin significantly as well.There are several B12 assessment methods available to providers, including serum/plasma B12, Mean Corpuscular Volume (MCV), Homocysteine (Hcy), Holotranscobalamin II (holoTCII), and serum and urinary Methylmalonic Acid (MMA). Urinary MMA has been found to be the most specific and sensitive of these markers when adjusted by kidney function (through serum creatinine levels) and while fasting Conclusion: Currently, there are no screening guidelines by the U.S.P.S.T.F or American Diabetes Association for cobalamin deficiency. However, neurologic deficits and macrocytic anemia could be prevented through monitoring cobalamin levels in diabetics receiving metformin treatment. This monitoring might be needed more in patients with seizure disorderon Carbamazebin.