Vitamin B12 screening desirable for T2DM patients who are metformin users, vegans or elderly

Singapore: A new study published in BMC: Primary Care has revealed that B12 deficiency is a highly prevalent and modifiable associated variable that aggravates the risks of type-2 diabetes mellitus (T2DM), especially in metformin users, vegetarians, and geriatric patients.

Singapore's rising population of older people and those with T2DM is concerning due to the increased risk of frailty and complications. B12 deficiency has a negative impact on the neurocognitive, hematological, and even immunological systems, compromising hopes for good aging.

The researchers investigated the determinants of B12 deficiency in community-dwelling patients with T2DM, aiming to profile patients most in need of B12-deficiency screening. The study evaluated a retrospective cross-sectional cohort of 592 primary-care patients with T2DM, recruited from 2008 to 2011 from a Polyclinic in Singapore.

The study revealed the following clinical findings:

1. B12 deficiency (serum B12 < 150 pmol/L) was present in 164 (27.7%) patients with T2DM.

2. B12 deficiency was associated with a higher metformin daily dose, age ≥ 80 years, vegetarianism, and folate deficiency.

3. Prescribed B12 supplementation was associated with lower odds of B12 deficiency.

4. Metformin daily dose correlated with Metformin 1-year cumulative dose and duration of diabetes.

5. Independent of the duration of T2DM, 29.3% of the B12-deficient patients needed > 1 screening test before the detection of B12 deficiency.

The lead author of the study, Dr. Andrew Kien Han Wee added that “The study recommends that primary-care screening for B12 deficiency should be part of the annual laboratory review of patients with T2DM, regardless of the duration of T2DM, especially when they are prescribed ≥ 1.5 g/day of metformin, ≥ 80 years old, vegetarian, and not prescribed B12 supplementation.”

The study also revealed that independent of the duration of T2DM, 29.3% of the B12-deficient patients needed more than one screening test before the detection of B12 deficiency. The researchers hope that their findings will encourage healthcare providers to prioritize regular B12 screening for T2DM patients, especially those at higher risk, and will help prevent the adverse effects of B12 deficiency.

Reference:

Wee, A.K.H., Sultana, R. Determinants of vitamin B12 deficiency in patients with type-2 diabetes mellitus — A primary-care retrospective cohort study. BMC Prim. Care 24, 102 (2023). https://doi.org/10.1186/s12875-023-02057-x