Effect of Vitamin B12 supplementation on glycemic control, albuminuria and peripheral neuropathy in diabetes mellitus patients – a cross sectional study

Objectives Type 2 Diabetes Mellitus (T2DM) is a global health challenge linked to microvascular complications like neuropathy and nephropathy. Metformin, first-line therapy, is associated with Vitamin B12 deficiency, potentially worsening neurological outcomes. This study assessed B12 supplementation’s association with glycemic control, albuminuria, and peripheral neuropathy. Methods A cross-sectional study at Hindu Rao Hospital, New Delhi, included 151 T2DM patients (≥30 years) on B12 supplementation. Serum B12, HbA 1c , and urinary albumin-creatinine ratio (ACR) were measured. Neuropathy was evaluated using the Diabetic Neuropathy Symptom (DNS) score. Analysis used SPSS v23; (p<0.05) was significant. Results Mean age was 50.79 ± 9.60 years (63.6 % female). Neuropathy prevalence (DNS≥1) was 76.8 %. Mean B12 was 452.25 ± 360.86 pg/mL. B12 levels differed significantly across glycemic groups (p<0.001), highest in HbA 1c >8.5 %. Neuropathy associated with B12 levels (p=0.027) and oral hypoglycemic use (p=0.010). Logistic regression showed higher B12 paradoxically linked to neuropathy (AOR=1.003; (p=0.023)). No ACR difference (p=0.879). Conclusions B12 shows complex ties to neuropathy and glycemic control in supplemented T2DM patients. Elevated serum levels may not indicate functional adequacy; monitoring functional markers like homocysteine or methylmalonic acid is recommended.