Background: Vitamin B₁₂ is a water soluble vitamin required for normal functioning of the brain and nervous system besides formation of blood. It has been reported that diabetic patients taking metformin has been said to be an important pharmacological cause of vitamin B₁₂ deficiency. Hence the aim of study is  to correlate serum B12 level with oral hypoglycemic agents(OHA) like metformin and sulfonylurea, and insulin therapy.

Material and methods: This is a cross–sectional study and was carried out in a group of 136 randomly selected diabetic patients in the Department of Medicine at Rajendra Institute of Medical Sciences, Ranchi  between  January  2016 to December 2017. Inclusion criteria were diabetic patients on metformin,sulfonyl urea and insulin or combination of any two. A control of 40 people from normal population was also taken. Vitamin B₁₂ estimation was done  by electrocheiluminescence immunoassay in all 136 patients.

RESULT: 84 (61.77%) of diabetic patients selected were on metformin treatment, 22(16.77%) of diabetic patients were on sulfonyurea and the rest 30(22.05%) of diabetic patients was on insulin. 16(11.76%) patients having vitamin B12 levels less than 180 pg/ml lie in the metformin group and  6(4.41%) patients in the probably low range (180–200 pg/ml) also lie in the metformin group. Significant difference in mean vitamin B12 levels in metformin group (412±193.16 pg/ml) and non–metformin group (549.27±80.40pg/ml), (p = 0.0261). Significant difference between mean value of vitamin B12 levels treated with metformin >12 months (305.87±151.94 pg/ml) and mean values of vitamin B12 treated with metformin < 12 months (553.50±147.14 pg/ml) (p < 0.0001).

CONCLUSION

There was significant difference between the mean values of vitamin B12 levels in the metformin group and in the sulfonylurea and insulin groups (p value 0.0261 and 0.0751 respectively). There was no statistical significant difference between the mean values of vitamin B12 in the diabetic population and the control from normal population (p value=0.6398).  We  concluded that vitamin B12 levels was definitely lowered with long term use of metformin.