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Author Notes:

Corresponding Author: Camille P. Vaughan, MD, MS, Atlanta VA Medical Center, 1670 Clairmont Road, Mailstop: 11B, Decatur, GA 30033, Phone: 404 321 6111 x 3710, Fax: 404 728 7779, camille.vaughan@emory.edu

Author Contributions: VK: Conception and design, analysis and interpretation of data, preparation of manuscript; JLE: analysis and interpretation of data, preparation and final approval of manuscript; BBP: interpretation of data, review and final approval of manuscript, NWH: interpretation of data, review and final approval of manuscript; TMJ: conception and design, interpretation of data, review and final approval of manuscript; AK: data compilation for analysis, review and final approval of manuscript; LSP: interpretation of data, review and final approval of manuscript; GPO: conception and design, interpretation of data, review and final approval of manuscript; CPV: conception and design, interpretation of data, preparation and final approval of manuscript.

See publication for full list of disclosures.

Subjects:

Research Funding:

This study was supported by the Department of Veterans Affairs Birmingham/Atlanta Geriatric Research, Education, and Clinical Center and a Veterans Health Administration Career Development Award (CDA-2) to Dr. Vaughan (1 IK2 RX000747-01).

This work was also supported in part by the Federal Drug Administration (FDA) award RO1FD003527 (L.S.P.), Veterans Affairs Health Services Research & Development Investigator-Initiated Research (VA HSR&D IIR) award 07-138 (L.S.P.), National Institutes of Health (NIH) awards R21DK099716 (L.S.P.) DK066204 (L.S.P.), U01 DK091958 (L.S.P.), U01 DK098246 (L.S.P.), and a Cystic Fibrosis Foundation award PHILLI12A0 (L.S.P).

The sponsors had no role in the design, methods, data collection, or analysis of the study and had no role in the preparation of the manuscript.

Keywords:

  • Science & Technology
  • Life Sciences & Biomedicine
  • Geriatrics & Gerontology
  • Gerontology
  • aging
  • metformin
  • type 2 diabetes
  • veterans
  • vitamin B12
  • PERIPHERAL-NERVE FUNCTION
  • DIABETES-MELLITUS
  • ADULTS
  • HOMOCYSTEINE
  • NEUROPATHY

Long-term Metformin Therapy and Monitoring for Vitamin B12 Deficiency Among Older Veterans

Tools:

Journal Title:

Journal of the American Geriatrics Society

Volume:

Volume 65, Number 5

Publisher:

, Pages 1061-1066

Type of Work:

Article | Post-print: After Peer Review

Abstract:

Objective: To examine the association between long-term metformin therapy and serum vitamin B12 monitoring. Design: Retrospective cohort study. Setting: A single Veterans Affairs Medical Center (VAMC), 2002–2012. Participants: Veterans 50 years or older with either type 2 diabetes and long-term metformin therapy (n = 3,687) or without diabetes and no prescription for metformin (n = 13,258). Measurements: We determined diabetes status from outpatient visits, and defined long-term metformin therapy as a prescription ≥500 mg/d for at least six consecutive months. We estimated the proportion of participants who received a serum B12 test and used multivariable logistic regression, stratified by age, to evaluate the association between metformin use and serum B12 testing. Results: Only 37% of older adults with diabetes receiving metformin were tested for vitamin B12 status after long-term metformin prescription. The mean B12 concentration was significantly lower in the metformin-exposed group (439.2 pg/dL) compared to those without diabetes (522.4 pg/dL) (P =.0015). About 7% of persons with diabetes receiving metformin were vitamin B12 deficient ( < 170 pg/dL) compared to 3% of persons without diabetes or metformin use (P =.0001). Depending on their age, metformin users were two to three times more likely not to receive vitamin B12 testing compared to those without metformin exposure, after adjusting for sex, race and ethnicity, body mass index, and number of years treated at the VAMC. Conclusion: Long-term metformin therapy is significantly associated with lower serum vitamin B12 concentration, yet those at risk are often not monitored for B12 deficiency. Because metformin is first line therapy for type 2 diabetes, clinical decision support should be considered to promote serum B12 monitoring among long-term metformin users for timely identification of the potential need for B12 replacement.

Copyright information:

© 2017, The American Geriatrics Society

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