Vitamin B12 Deficiency Associated With Concomitant Metformin and Proton Pump Inhibitor Use

Metformin and proton pump inhibitors have been implicated in decreasing levels of vitamin B12 independently. The purpose of this study was to evaluate the effect of concomitant use of metformin and proton pump inhibitors on the incidence of vitamin B12 deficiency.A retrospective chart review was done using the computerized patient record system at the Memphis VA Medical Center for 614 patients with type 2 diabetes and previously collected vitamin B12 levels. Patients were excluded if they were over the age of 60 years; on a vegetarian diet; had been diagnosed with pernicious anemia, documented by a positive Schilling test or anti-intrinsic factor antibody, or pancreatic exocrine insufficiency; had undergone a gastrectomy or bowel resection; or had been treated with supplemental calcium, H2 blocker, or B12 within 3 months of data collection. The vitamin B12 levels were assessed …