Serum Vitamin B12 Levels among Type 2 Diabetic Patients Maintained on Metformin Based Oral Anti-Diabetic Drugs - An Observational Study

Abstract

The study was aimed to assess the serum vitamin B12 status of diabetic patients managed on metformin mono or combination therapy. A total of 45 patients (25 males; 20 females) diagnosed with type 2 diabetes for less than 3 years were enrolled into the study. Two groups were formed - metformin monotherapy or Gp1 (21 patients, mean age = 42.8 ± 6.82 years) and combination therapy group or Gp2 (24 patients, mean age = 42.6 ± 7.05 years). It was a self-control study wherein their serum vitamin B12 was measured at baseline (initial) and after 6 months (final). Demographic profile was obtained at baseline. Dietary intake of vitamin B12 was assessed by 3 days recall, while clinical manifestations of B12 deficiency and metformin dosages were obtained at initial and final period. Mean dietary intake of vitamin B12 was 1.16 ± 1.01 μg/day at baseline and 1.25 ± 1.15 μg/day at the sixth month, in the two groups. The mean serum B12 levels of group 1 and 2 at baseline were 347.54 ± 146.10, 293.47 ± 90.90 pg/ml, respectively and those at sixth month were 296.24 ± 144.45 and 239.32 ± 89.90 pg/ml respectively. The mean reduction in serum B12 was 51 and 54 pg/ml in Gp1 and Gp2 respectively, during the six-month observation period and the difference was statistically significant (P = Gp-1; 0.001, Gp-2; 0.002). An inverse relation was found between serum B12 and dosage of metformin. The proportion of patients with weakness, tingling/numbness in hands/feet increased markedly in the sixth month in both the groups. Patients on metformin, both alone or in combination, need monitoring and appropriate management of B12 deficiency.