Trends in Vitamin B12 Level Testing in Patients on Metformin From 2000 to 2020

Abstract

Background and Objectives: Metformin is one of the primary pharmacologic agents for managing type 2 diabetes mellitus (T2DM). However, it has been associated with interference in vitamin B12 absorption and deficiency. Vitamin B12 deficiency and T2DM can present diagnostic challenges for polyneuropathy. Diagnosis is essential for guiding treatment, yet the use of vitamin B12 level testing in this population may have dwindled over time amid changing practice guidelines. This study examines trends over time in the use of vitamin B12 level testing among patients on metformin. Methods: This retrospective trend analysis used data from TriNetX, a real-world, longitudinal clinical database. Patients treated with metformin from 2000 to 2020 were identified using Rx Concept Unique Identifier codes. The number of patients who underwent vitamin B12 level testing at any time after 1 month from metformin initiation was tabulated. Patients were grouped by the year of B12 level testing. Trends in B12 level testing were assessed using the Jonckheere-Terpstra statistical test (P