B12 Deficiency: It's Not Always about Nerves!

Background:

Vitamin B12 deficiency can have numerous health consequences including neurological dysfunction, immune dysfunction, and decreased cognitive function [1,2]. It is lesser recognized that B12 deficiency can result in anemia as well as other cytopenias often seen on CBCs collected during visits with first-contact physicians. This leads to delayed or missed diagnosis of B12 deficiency. The primary objective of the current study is to assess physician knowledge gaps in diagnosing B12 deficiency and adequate workup for cytopenias before referring to a hematologist.

Methods:

This study is a retrospective chart review of 862 adults (Mean age 52.9 ± 18.4, 497 female) seen in a single-provider non cancer hematology clinic at an academic center between February 2020 and July 2023. Data collection included patient demographics, referral reason or diagnosis, referring provider specialty type, and the diagnosis made by the consulting adult classical hematologist in this clinic. Patients lost to follow-up after initial referral have been excluded from this data analysis. B12 deficiency was defined as B12 <400 pg/ml.

Results:

Out of 862 analyzed referrals to this clinic, only 3 included vitamin B12 deficiency within the reason for referral. Of the 360 patients who were referred for various cytopenias (Anemia 43%, Thrombocytopenia 23%, Neutropenia 21%, Bicytopenia 6.5%, Pancytopenia 6.5%), 24% were diagnosed with B12 deficiency by this classical hematologist. Of note, 14% of these B12 deficient patients were referred from Hematology/Oncology providers. Further workup by this classical hematologist showed that 17% of cytopenia cases only had B12 deficiency, while the cause of cytopenia in the remaining was found to be multifactorial and they were found to have other vitamin/mineral deficiency, autoimmune conditions, or viral infection in addition to B12 deficiency. None of the B12 deficient patients presented to this clinic with neurological signs or symptoms.

Conclusion:

Data presented here demonstrates that diagnosing B12 deficiency and adequate work up for cytopenias are a challenge both in primary care and specialty clinics, including Hematology/Oncology specialists. Educational interventions are necessary to improve healthcare providers' skills for timely diagnosis of B12 deficiency and etiology of cytopenias before referring to a hematologist. Last but not least, adding a classical hematologist to the care team for patients with non-cancer blood disorders improves patient outcomes.

Citations:

1. Kumar N. Neurologic aspects of cobalamin (B12) deficiency. Handb Clin Neurol. 2014;120:915-26. doi: 10.1016/B978-0-7020-4087-0.00060-7. PMID: 24365360.

2. Green R, Miller JW. Vitamin B12 deficiency. Vitam Horm. 2022;119:405-439. doi: 10.1016/bs.vh.2022.02.003. Epub 2022 Mar 11. PMID: 35337628.

Pakbaz:Agio: Consultancy, Speakers Bureau; Alexion: Consultancy; Amgen: Research Funding; Novonordisk: Research Funding; Pfizer: Research Funding; Novartis: Consultancy, Research Funding; Pharming: Consultancy; Sanofi: Consultancy; ScientiaCME: Consultancy; Sobi: Consultancy, Speakers Bureau; Vertex: Consultancy.