KUMJ | VOL. 23 | NO. 5 | ISSUE 93 | DECEMBER, 2026
Prevalence and Risk Factors of Vitamin B12 Deficiency in Type 2 Diabetes Mellitus Patients on Metformin at a Tertiary Care Center of Nepal
Sapkota P, Tamang A, Lamsal P, Dhakal K, Mahato A, Pasakhala K, Humagain S
Abstract: Background
Vitamin B12 deficiency is a common but often underrecognized complication in
patients with type 2 diabetes mellitus (T2DM) undergoing long-term metformin
therapy. If undetected, it may lead to serious complications including neuropathy,
cognitive decline and anemia.
Objective
To determine the prevalence and risk factors of vitamin B12 deficiency in type 2
diabetes mellitus (T2DM) patients on metformin at a tertiary care center in Nepal.
Method
An analytical cross-sectional study was conducted among 318 patients with type 2
diabetes mellitus (T2DM) receiving metformin therapy. Serum vitamin B12 levels
and relevant clinical and demographic data were collected. Descriptive statistics
summarized baseline characteristics, while univariate and bivariate analyses were
done. Multivariable logistic regression was then performed to identify independent
predictors of vitamin B12 deficiency. Statistical significance was set at p < 0.05, and
all analyses were conducted using Stata version 14.
Result
Vitamin B12 deficiency was observed in 21.7% (69 out of 318 participants).
Multivariable regression analysis identified age (AOR: 1.07; 95% CI: 1.04 to 1.08;
p < 0.001), metformin dose (AOR: 1.002; 95% CI: 1.001 to 1.003; p < 0.001) and
longer metformin use (AOR: 1.11; 95% CI: 1.03 to 1.19; p = 0.005) were significantly
associated with higher odds of deficiency. No significant associations were found
with sex, smoking, alcohol use, vegetarian diet, HbA1c, lipid profiles, neuropathy,
retinopathy or serum creatinine (p > 0.05).
Conclusion
Vitamin B12 deficiency is prevalent among metformin-treated T2DM patients, with
age, duration and dose of metformin as key risk factors. Regular monitoring and
supplementation are crucial for this patient population.
Keyword : Metformin, Nepal, Type 2 diabetes mellitus, Vitamin B12 deficiency
