ArticlePharmacy practice
Evaluation of vitamin B12 monitoring in patients on metformin in urban ambulatory care settings.
Article in Pharmacy practice. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 7 papers.
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The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
7 citing papers in PubMed, 10 citations in OpenAlex.
- Vitamin B12 Supplementation in Diabetic Neuropathy: A 1-Year, Randomized, Double-Blind, Placebo-Controlled Trial.Nutrients · 2021Trial
- Vitamin BBMJ open · 2026Article
- Article
- Clinician awareness and implementation of vitamin BBMC primary care · 2026Article
- Trends in Vitamin B12 Level Testing in Patients on Metformin From 2000 to 2020.PRiMER (Leawood, Kan.) · 2024Article
- Clinical Pathobiochemistry of Vitamin BNutrients · 2023Review
- A review of therapeutic options for managing the metabolic aspects of polycystic ovary syndrome.Therapeutic advances in endocrinology and metabolism · 2020Review
Corrections and comments
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Authors and funding
6 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundPrevious studies linked metformin use to vitamin B12 deficiency and demonstrated that the prevalence of vitamin B12 monitoring remains low.
objectiveThis study aimed to assess the occurrence of monitoring vitamin B12 levels in a diverse population.
methodsThis was a retrospective chart review of adult patients with type 2 diabetes on metformin doses ≥ 1000 mg for ≥ 6 months at five Federally Qualified Health Centers (FQHC) and one Program of All-Inclusive Care for the Elderly (PACE). Charts were reviewed for occurrence of monitoring vitamin B12 levels in the past 5 years. Data collected included patient demographics, laboratory data, other potential vitamin B12 level lowering agents, active prescription for vitamin B12 supplementation, concomitant diabetes medications and metformin total daily dose.
resultsOf the 322 patients included, 25% had a vitamin B12 level measured in the previous five years. Among the patients with a vitamin B12 level, 87.7% were within the normal range (>350 pg/mL), 11.1% were low (200-300 pg/mL), and only one patient (1.2%) was deficient (<200 pg/mL). These patients were older (69.2 vs. 56.4, p<0.001); more likely to be white (56.8% vs. 37.8%, p=0.04); and more likely to use proton pump inhibitors (34.6% vs. 20.7%, p=0.02) and vitamin B12 supplementation (27.2% vs. 4.6%, p<0.001). Vitamin B12 monitoring differed between the FQHC (15.2%) and PACE (97.4%) sites (p<0.001). Each greater year of age was associated with a 5% increased odds of vitamin B12 monitoring (a OR: 1.05; 95% CI: 1.02-1.08).
conclusionsThe majority of patients seen at the FQHC sites did not have vitamin B12 levels monitored, however, most of the patients who were monitored had normal vitamin B12 levels, which may warrant extending the monitoring time. This finding may also support monitoring patients who have additional risk factors for vitamin B12 deficiency such as concurrent medication use with other vitamin B12 lowering agents or clinical symptoms of deficiency such as peripheral neuropathy. Future studies are needed to determine appropriate frequency of monitoring.
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