Prevalence of Vitamin B12 Deficiency Among Patients With Type 2 Diabetes Mellitus on Long-Term Metformin Therapy

BACKGROUND: Vitamin B12 insufficiency, which aggravates hematological and neurological problems in diabetics, has been linked to chronic metformin therapy, the main treatment for type 2 diabetes mellitus (T2DM). This study aimed to assess the prevalence of vitamin B12 deficiency in patients with T2DM on metformin and identify associated clinical and demographic factors in an Indian tertiary care setting. METHODOLOGY: An observational cross-sectional hospital-based study was conducted among adults with T2DM. Sociodemographic data, clinical history, diabetes duration, medication use, and laboratory parameters were recorded. Serum vitamin B12 levels were measured using standard laboratory cutoffs to identify deficiency, and data were analyzed using appropriate descriptive and inferential statistical methods. RESULTS: Among 170 participants, multivariate logistic regression analysis identified metformin use for more than five years (adjusted odds ratio (OR): 2.85; 95% confidence interval (CI): 1.32-6.12), concomitant pantoprazole use (adjusted OR: 2.41; 95% CI: 1.08-5.34), and low high-density lipoprotein cholesterol levels below 40 mg/dL (adjusted OR: 2.22; 95% CI: 1.01-4.91) as independent predictors of vitamin B12 deficiency. Low hemoglobin levels, elevated low-density lipoprotein cholesterol levels, and poor glycemic control were not significantly associated (p > 0.05). CONCLUSION: Patients with T2DM, especially those on long-term metformin medication, frequently lack vitamin B12. Timely supplementation and routine screening might help lower avoidable consequences.